The crown of Jerusalem is the Old City, where the traditions of three great religions still reign, where bell towers and minarets intermingle with domes and red-tiled roofs to create a unique urban fabric. A 16th-century wall, built by Suleiman the Magnificent after the Turks conquered Jerusalem, has halted the encroachment of modernization and helped preserve the medieval character of the city.

Recently, the Israeli Ministry of Tourism and the Jerusalem Municipality completed a long-term project of repaving the footpath on top of the ramparts, which Turkish soldiers first patrolled over 400 years ago, and opened the Wall to walkers. This "Ramparts Walk" is the best introduction to the Old City that lies within it and to modern Jerusalem, which began to spread away from it in the 1860s.

The Old City occupies an area slightly smaller than one square mile. "A fast walker," said Mark Twain in 1867, "could go outside the walls of Jerusalem and walk entirely around the city in one hour. I do not know how else to make one understand how small it is." Yet no other place on earth embraces such a profusion of Holy Places, synagogues, churches and mosques. The city has been a center of pilgrimage since the days of David and Solomon. It is filled with archeological treasures, many of which have been excavated since 1967. Even Suleiman's 1530s Wall rests upon older foundations dating back to the Hasmoneans -- the dynasty of Hannukah fame -- Herod and Hadrian.

But the Old City is not a museum; it is alive and vibrant, teeming with people from all over the world, its markets an extravaganza of colors, aromas and sounds.

The streets of the Old City still follow the grid pattern laid out by Hadrian in 135 A.D., after the Bar Kochba Revolt, when the emperor rebuilt the city along the lines of a Roman colony and renamed it Aelia Capitolina. The grid is not completely symmetrical. The Temple Mount platform, which still occupies about a fifth of the city, was so solid that even the Romans could not destroy it. And the Tyropoeon valley, which crosses the city diagonally, prevents continuous parallel streets.

The Old City is divided into four quarters of unequal size: the Christian, Moslem, Jewish and Armenian Quarters. This division became permanent after the defeat of the Crusaders in the 13th century, as each group congregated around its Holy Places.

In the 19th century, ancient defense walls were deemed useless in Europe and were often torn down to allow for development; but by then the Ottoman Empire was crumbling and Jerusalem's Wall was saved through neglect.

The Wall is about 2 1/2 miles long; its average height is 30 feet, its average width six feet. The lowest point is the Dung Gate, at 2,380 feet above sea level; the highest is the New Gate, at 2,590 feet. There are eight gates, one of which is closed.

Like most houses in the city, the Wall is built of the locally hewn grayish stone. The elements and pollution have not been kind to the masonry, which now looks weathered and drab. But at dawn and in the twilight hour, the rays of the sun touch the Wall and tint it golden and rose.

A walk on the Wall offers a view from the top, a glimpse into back yards where pines, oleanders, cypresses and lemon trees grow, where geraniums flourish in tin cans. Here and there brown roosters peck in the dirt and laundry flutters in the wind.

The "Ramparts Walk" can be taken daily between 9 a.m. and 5 p.m., Friday until 2 p.m. Tickets are not sold on Saturday but may be purchased in advance. The fee is $1 and it allows for four separate visits over a two-day period. One cannot actually walk completely around the city on top of the ramparts, since at one point the Wall becomes part of the enclosure of the Temple Mount where the Dome of the Rock and the Mosque of El-Aqsa now stand. (Moslems allow visitors into these shrines during certain hours, but they don't like people wandering on their part of the Wall.)

The walker is faced with a choice of five starting points and various routes; the following walk is a suggested course done in two parts. It allows for visits to sites adjacent to the Wall and takes into consideration the hilly terrain: There are many stairs on the Wall and it is less tiring to explore it in two stretches. Nonskid shoes, a sun hat and long pants are highly recommended.

A logical beginning is Jaffa Gate, for centuries the main entry to the city for pilgrims coming from the West. In a niche outside the gate is an inscription commemorating the "Great Sultan Suleiman . . . who gave the order to build this blessed wall" in 1538. A ticket booth is within the gate, up one flight of steps. From the gate's roof there is an excellent view of modern, west Jerusalem, separated from the Old City by the Valley of Hinnom. Called Gai Ben Hinnom in Hebrew, the origin of the word gehenna (hell), the valley was presumably the place where children were sacrificed to the Molech in the days of King Menasseh. Today the valley is green and serene, the scene of public concerts and other artistic performances. Beyond it rise 19th-century Jewish neighborhoods, Mishkenot Sha'ananim and Yemin Moshe, characterized by their red-tiled roofs. On the horizon is a host of high-rise hotels. Across the street from the gate, to the south, stands the Citadel.

The walk on the ramparts leads north. Through gun slits used by Turks of yore are glimpses of the new Jerusalem. Within the Wall is the Christian Quarter; the Latin Patriarchate, with its bell tower and gabled entrance, is easily distinguished. At the northwestern corner, known as Tancred's Tower, the Crusaders breached the Wall in 1099. Today, outside the Wall, stands a poke-marked building with an arched convex fac,ade. It is Mayor Teddy Kollek's Municipality, built by the British in the 1930s at this strategic location to bridge the Old City and the new one.

In 1948 one of the fiercest battles for Jerusalem took place here, hence the bullet holes in the Municipality. Until 1967 the border ran through the middle of the street that separates the Municipality from the Wall; Jordanian and Israeli soldiers used to shoot at each other across the street.

Around the corner, within the Wall, is a green dome said to mark the tomb of "The Light of the Moon," a Moslem princess. Next is the New Gate, opened in 1887 to permit Christian pilgrims a more direct approach to the Church of the Holy Sepulchre. One can get off the Wall at the New Gate.

The northern section of the Wall begins to descend at the New Gate. To the right is Terra Sancta and the tower of St. Saviour's Convent, the headquarters of the Franciscans in the Middle East. A bit past it is a courtyard filled with rusting metal sheets and other junk. Beyond it, to the south, appear the two domes of the Church of the Holy Sepulchre, flanked by minarets. All around are houses covered with centuries-old stone cupolas, patched with tar to keep out the rain; solar heaters and a sea of TV antennae bring back the present.

Damascus Gate, by far the handsomest entry to the Old City, stands at the beginning of the road that leads north to Damascus and Istanbul, Suleiman's capital. Considered fit for royal visitors, the crenelated gate is highly ornate. Yet any gate constitutes a weak point in a defensive wall, this one being particularly vulnerable since Jerusalem is not protected by ravines on the north. Thus the gatehouse is shaped like a "Z," a design the French call porte en chicane, a "tricky gate," meant to confuse the enemy. The 16th-century entry incorporates the remains of a tower and a gate from Hadrian's time and ashlars from the Herodian period. Recently excavated and opened to the public, the remains are well worth a visit.

From the top of Damascus Gate wide vistas open up. Inside the Old City the road splits. On the right it becomes Suq Khan ez-Zeit, built along the line of the Roman cardo, the north-to-south axis of the city; today it separates the Christian and Moslem Quarters. On the left it is El-Wad Road, which follows the course of the Tyropoeon valley. In biblical times it ran between the Temple Mount and the Upper City.

From here one also gets a good view of the golden Dome of the Rock as it rises majestically from the Temple Mount, uncluttered by other structures. The platform on which it stands was originally built by Solomon in the 10th century B.C., and enlarged by Herod almost 1,000 years later. Closer to the gate the houses of the Moslem Quarter cling to the hillside, their doorways painted blue to ward off the evil eye. North of Damascus Gate sprawls modern Arab Jerusalem. It is possible to get off the Wall (and on) at Damascus Gate.

Just after a steep climb, when the Wall levels off, a look outside reveals a large rock, in back of the bus station, its face resembling a skull, golgolet in Hebrew. Some believe that this is the true location of Golgotha, the hill where Jesus died.

The Wall continues past Herod's Gate, another possible exit. Between here and the Rockefeller Museum, Godfrey de Bouillon broke through the Moslem defenses and became the first Crusader to enter the Holy City. Inside the Wall are large empty fields, a rare sight in the crowded city. Gypsies live here, in tin-covered shacks.

The northeastern corner of the Wall is called Burj el-Laqlaq in Arabic, "Tower of the Storks," where every Friday at dawn the Sheep Exchange begins. Arabs from all over arrive with sheep, goats and an occasional donkey, to bargain, barter and trade.

To the east are Mount Scopus and the Mount of Olives, part of the watershed that forms the border between the city and the Judean Desert. On the summits of the mounts are three towers: The one to the north marks the location of the 1920s campus of Hebrew University; the middle one is Augusta Victoria, named for the German empress who visited the spot in 1898, and to the south is the belfry of the Russian Convent, which dates back to the 1880s.

The slope of the Mount of Olives is divided between two religions. Olive trees at Gethsemane and several churches represent Christian traditions; thousands of white tombstones cover the rest of the slope, an ancient Jewish cemetery. Beyond loom the azure hills of Moab. Between the city and the mountains is the Valley of Jehoshaphat, which derives its name from the Hebrew words for "God" and "to judge." Since the days of the prophet Joel, this has been the appointed scene for the day when God "will gather all the nations . . . and enter into judgment with them."

The first part of the walk comes to a halt at the Lions Gate, where the Haram esh-Sharif, the Moslem sanctuary on the Temple Mount, begins. One can then enter the gate and continue along the street, which soon becomes Via Dolorosa. Within a hundred yards is St. Anne, built by the Crusaders, the most beautiful church in Jerusalem. Where Via Dolorosa meets El-Wad, a turn to the left will take the walker past the Western Wall to the Dung Gate, a turn to the right leads to Damascus Gate. Taxis and buses are available at either gate.

For anyone who wishes to "walk about Zion, and go around about her," as the Psalms suggest, it is possible to turn right just outside the Lions Gate and walk along the Wall through the Moslem cemetery. Soon one passes the Golden Gate, blocked since the early days of Islam, through which Jews believe the Messiah will enter Jerusalem. A tip of a pillar embedded in the Wall is known as "Mohammed's Seat where the Prophet will sit on the Day of Judgment."

Near the southeastern corner of the Wall is the "seam" where Herodian masonry from the first century B.C. joins an earlier structure. South of the Wall here, a vast, recently excavated site can be seen. Its monumental staircase, with some steps found in situ, leads to the Hulda Gates, through which worshipers entered the Temple 2,000 years ago. A bit further west is the Dung Gate.

The second part of the "Ramparts Walk" is only half as long as the first. It begins at the Citadel, next to Jaffa Gate. In 1898, the part of the Wall that connected the gatehouse and the Citadel was removed by the Turks to make way for Kaiser Wilhelm II and his entourage.

Also known as the Tower of David, the Citadel is a good place in which to become familiar with the eclectic handiwork of Jerusalem's many occupiers. Strategically located on the western hill, the Citadel has served as a military base for over 2,000 years. Often the last stronghold in time of war, the Citadel's fall frequently signified the fall of Jerusalem. The site is open daily from 8:30 a.m. to 4 p.m., Friday till 2 p.m.; entry fee is $1.25. In the courtyard are the remains of Hasmonean walls and a defense tower from the second and first centuries B.C., and a Herodian tower built by the king to guard his palace and spared by the Romans in 70 A.D. when the rest of the city was destroyed.

Early Christian pilgrims mention this place in their writings. The Israelis recently excavated part of a round corner tower built in the early Moslem period, circa 700. In 1099 the Citadel was the last place in Jerusalem to surrender to the Crusaders. Much of what we see today was built either by the Mamelukes after 1250, or by Suleiman in the 16th century.

There is a small museum on the site that contains many of the artifacts left behind by the garrisons of a dozen armies, from catapult stones to Turkish coffee cups. Well marked and accompanied by maps and charts, the objects -- together with the Citadel's patchwork of vaults, towers and moats -- tell the history of Jerusalem.

The beginning of the second part of the "Ramparts Walk" is just south of the Citadel, up a spiral staircase. The view outside the Wall is of west Jerusalem; inside are the police barracks, built in 1838, and other buildings in the Armenian Quarter. In the background is the Cathedral of St. James, a Crusader structure built on earlier remains.

Once around the southwestern corner of the Wall, the Franciscan and Armenian cemeteries can be seen on top of Mount Zion. Nearby is the so-called Tomb of David, adjoined by a mosque, a synagogue and the Cenacle, the Room of the Last Supper. There are two such rooms on Mount Zion. The summit is dominated by the Dormition Abbey, built in 1910, associated with Mary's death. Next is Zion Gate, where one can get off the Wall (or onto it).

If one continues to walk on the ramparts, the Jewish Quarter appears. Chants and prayers emerge from dwellings and houses of worship. Near the Wall once stood the "Nea" Church, built by Justinian in the sixth century.

It is actually more interesting to get off the Wall at Zion Gate and complete the walk along the path that meanders through the parks with which the Israelis have surrounded the Old City. Trees, shrubs, flowers and grass have been planted amidst relics from different eras, to create a haven for resident and tourist alike. The descent to the Dung Gate, named for a portal mentioned in Nehemiah, passes by baths and cisterns from Herod's time, plus sections of walls, towers and pavements from other periods, all well marked.

Within the Dung Gate is the entrance to the Temple Mount Excavations. (There is an English tour daily, except Saturday, at 2 p.m. The fee is $2.) This most important archeological site includes the monumental staircase to the Temple.

But before entering the Dung Gate, pause and look down at the western slope of the Valley of Jehoshaphat from where the City of David began spreading north and west. David was the king who made Jerusalem the capital of his people; 3,000 years later the struggle for possession continues.