As a major European crossroad, Frankfurt reportedly has some 18,000 hotel beds. So why, I wondered, didn't Germany's city of skyscrapers have just one for me? "Nope," said my travel agent. "All booked," said German tourism officials. The closest room I could find was a 45-minute train ride away in Wiesbaden, a historic spa resort.

A full house? I probably should have expected it in the city that German tourism officials say is the country's most heavily visited. As luck would have it, I had scheduled my trip when the city was playing host to one of its frequent international trade fairs -- as, indeed, it has for hundreds of years. For these big events, hotel rooms often are reserved a year ahead. I never had a chance.

Frankfurt is an attractive, cosmopolitan city with a long and lovely riverfront, but its ranking on the popularity charts can be a little misleading. That stems mostly from the city's roles as an ancient and prosperous capital of international commerce and as an important modern-day gateway to central Europe. "Bankfurt" it is sometimes called by the nation-hopping business travelers who flock there year-round. If you are a tourist flying to Germany, Frankfurt's airport is probably where you will land -- it's the country's busiest. The city also is a major hub in Europe's motorway network, and it boasts the largest train station on the continent.

But high-powered commerce is not the stuff of romantic travel, and Frankfurt is skipped over by many tourists. I had passed through twice before without stopping. Too modern and too dull, I thought -- but I was wrong. The city's heritage dates back to the days of the Roman Empire, and there are plenty of cultural and historical treasures amid the rich banks and tall buildings. At times, normally stolid, pin-striped Frankfurt can seem positively festive.

At the foot of the modern towers, quaint vestiges of an older Europe remain, and the streets, lined with inviting sidewalk cafes, bustle with vitality. Pretzel vendors are everywhere. A business traveler might want to take a day off to look around the city where the Rothschild family founded its banking empire two centuries ago. As a tourist, I found the city a pleasant introduction to Germany and Central Europe while I was recovering from transatlantic jet lag.

As for Wiesbaden, it proved to be an agreeable bonus on my itinerary. Quieter and less formal than Frankfurt, it welcomed me back from my commute each night with cozy neighborhood cafes serving hearty German fare with lots of sausages and hefty steins of beer. One night, I even joined in on a couple of rollicking sing-alongs to an oompah band.

Frankfurt's soaring skyline can be intimidating, but the old heart of the city -- the Inner City -- is surprisingly intimate. Small in area and ringed by a series of parks that follow the arcing path of the old city walls, it is comfortably walkable -- a bonus for business travelers and tourists alike. Pedestrian-only avenues lead uphill from the north bank of the Main River to the Romerberg, Frankfurt's five-sided town square, and beyond to the Zeil, a tree-shaded promenade lined with fine boutiques and department stores.

Much of the Inner City was damaged or destroyed by bombing during World War II, and only a few historic buildings have been restored to their original appearance. Among them are the Goethe House, the birthplace of the poet Johann Wolfgang von Goethe; the red sandstone Cathedral of St. Bartholomew, and the Romer, Frankfurt's ornately gabled Town Hall that has been the city's symbol for centuries. They stand as cherished exhibits in an Inner City that today has the look of a spacious, shrubbery-filled sculpture garden.

On the south bank of the river, just across the Eiserner Steg footbridge, is medieval Sachsenhausen, a picturesque, mostly traffic-free jumble of half-timbered houses and winding streets. Once the home of craftsmen, dozens of the buildings now have become taverns, serving up Frankfurt's traditional ebbelwei (apple wine) to tourists and locals alike. Though just a few steps from modern Frankfurt, Sachsenhausen -- or Alt-Sachsenhausen, as it is also called -- is centuries removed. And on evenings and weekends, it comes alive.

Tradition in Sachsenhausen, it seems, is very important. The ebbelwei -- sweetest tasting in the fall -- arrives at the table in a little blue and gray ceramic jug called a bembel, and you drink it from a clear, slender glass called a schobbeglas. The wine customarily is accompanied by handkas mit musik, which actually is a soft cheese nibbly mixed with chopped onions, vinegar and oil and spread on hunks of dark bread. I figured with one round of apple wine I had doubled my German vocabulary.

An easy stroll from the tavern district is the Frankfurt Museumsufer, a collection of seven museums that line the south bank of the Main like troopers on parade. A shady riverside promenade, dotted with park benches, connects them all. Each has an impressive view across the river to the Inner City. I found the most interesting of the seven to be the Museum of Arts and Crafts, a collection of craftworks from around the world. They are housed in an elegantly austere white structure designed by famed New York architect Richard Meier. His building is an artwork itself.

I enjoy cities and city life, so I'm always delighted to find neighborhoods or districts that seem to reflect cities at their best. For me, Frankfurt's Inner City and Sachsenhausen, facing each other across the Main, easily qualify. They are architecturally interesting with their mix of old and new, lots of fun and blessedly free of noisy traffic.

A visitor in a hurry, and that appears to be every tourist in Frankfurt, can make a fairly complete circle tour of the Inner City and Sachsenhausen in an easy half-day's ramble. You might need another day to see the museums. The German National Tourist Office in New York, and Frankfurt's tourist information office on the Romerberg distribute an English-language brochure detailing short or extended walking itineraries in both areas.

I had the brochure in hand when I stepped off the morning commuter train from Wiesbaden for my first good look at Frankfurt. The ride had been swift and uneventful, although I had some initial difficulty figuring out where to buy a train ticket and how much it cost. A couple of folks who spoke as little English as I do German managed to educate me. Commuter tickets are sold in a vending machine, and a chart indicates the price. However, I first had to find coins for the machine. Still groggy from missed sleep when I arrived at the station, I woke up quickly when confronted with this tricky exercise.

The Frankfurt station, a vast 19th-century structure, is about a six-block walk from the Romerberg. The neighborhood immediately outside the station obviously is dedicated to pornography. I took a route, however, that led alongside the north bank of the Main River, where I could watch the boat traffic. Long, slender barges transport the commodities that fuel a booming economy. Across the river, Meier's museum is easily recognizable.

Behind the Romerberg soar Frankfurt's modern high-rises, but if you ignore them you might easily believe you have strolled into a medieval town square. Most of it had to be rebuilt after the war, though the replacement buildings manage to look centuries old. Frankfurt is said to have been one of Germany's most beautiful cities before the war. More than a hint of that old beauty remains in the Romerberg.

On the west side of the square is the reconstructed Romer, three adjoining townhouses that collectively have served as Frankfurt's Gothic-gabled Town Hall since 1405. Opposite it is the Ostzelle, a picturesque row of half-timbered houses of stone. And beyond them is the imposing, many-pinnacled spire of the cathedral, which originally was built in the 13th century. For centuries, German kings and emperors were crowned there.

The Goethe House, also a post-war reconstruction, is a five-minute walk from the square, though I confess I got momentarily lost in the tangle of streets getting there. A place of pilgrimage for fans of Goethe -- I had relished Goethe's "Italian Journey" on my own trip through Italy -- it is actually two adjoining houses, originally built in the 16th century. Goethe was born in 1749 in the larger of the two.

Reduced to ashes on March 22, 1944, the five-story house was rebuilt using materials retrieved from the rubble, including unbroken blocks of fallen red sandstone, wrought-iron window gratings and a screen at the entranceway with the initials of Goethe's father, an imperial official. Period furnishings, a few of them belonging to the Goethe family, also were saved.

A museum displays documents and other Goethe memorabilia -- as well as photographs of the war damage. But the house itself is interesting as an example of well-to-do life in Frankfurt in the 18th century. An English-language brochure, sold at the house, points out such fashionable furnishings as Bohemian chandeliers, rococo mirrors, Chinese-patterned wallpaper and an ornate wrought-iron balustrade.

Just east of the Goethe House, modern fashions can be seen in abundance on the Zeil, a half-mile-long pedestrian avenue, lined with fancy shops and inviting cafes. It is a colorful part of town, where local folks of all ages gather to stroll, gossip and window-shop. Almost everybody, myself included, seemed to be carrying an ice-cream cone.

The boundary between the Inner City and modern Frankfurt is marked by the Wallanlagen or Rampart Gardens, a curving strip of greenery and ponds where the city's old walls once stood. On the western end near the Main River is a collection of statuary honoring German artists, including Goethe and Beethoven. Goethe, whose statue I was seeking, looks properly creative in flowing robes and wind-tossed hair.

At lunchtime, I crossed the Main to one of old Sachsenhausen's many taverns. Heavy beams and wood paneling provided Teutonic atmosphere, as did the menu. I ordered a bowl of liver noodle soup, dark bread and, of course, a glass of apple wine poured from the traditional clay jug. The best I can say about the wine is that it was drinkable, though barely. My wife ordered beer, and so did I when it was time for a refill.

The seven museums of the Museumsufer awaited, but seven in an afternoon would be a challenge for anyone. As any sensible tourist would, I picked those that intrigued me.

The most interesting for an American -- well, for me, anyway -- are the Museum of Arts and Crafts, as much for the Meier building as the exhibits; the Stadel Art Institute and Municipal Gallery, which has an excellent collection of the works of Europe's Old Masters; and the Liebieghaus, one of the continent's finest museums of sculpture. The others are the Museum of Prehistory and Early History, the Film Museum, the Museum of German Architecture and the Federal Post Office Museum.

In this walkable city, it would have been nice to walk back to my hotel as evening approached. Instead, I boarded the train again for the return trip to Wiesbaden. So I really don't know how the residents of Frankfurt spend their evenings. In Wiesbaden, I ate superb schnitzel, drank more beer and sang along with the neighborhood folks there. Not getting a room in Frankfurt was no hardship at all.

WAYS & MEANS GETTING THERE: United, Pan Am and Lufthansa fly nonstop from Dulles/Washington International to Frankfurt. High-season fares currently are in effect, but for the upcoming shoulder season, Oct. 1-31, United is quoting a fare of $664, based on a 30-day advance purchase and travel on weekdays; for weekend travel, the fare is $714. The low season begins Nov. 1, when the fare drops to $560 on weekdays and $610 on weekends. Airport and other fees are an additional $28. The airlines also may act to impose a fuel surcharge of about 10 percent because of the Iraqi situation. WHERE TO STAY: Frankfurt can and does book full when the spring and fall international trade shows are in town. The German National Tourist Office in New York can give you the dates when accommodations are the tightest, but double-check because the staff is not infallible. I was told by an information clerk I would have no trouble finding a room on the days I planned to visit the city. In fact, my trip coincided with one of the largest trade fairs of the year -- something I learned only after I had paid for nonrefundable airline tickets.

Frankfurt has many excellent hotels and pensions. A list, describing facilities and rates, is available from the German National Tourist Office. A room for two in a pension begins at about $65; a room in a good hotel runs from about $130 to $250. WHERE TO EAT: The German National Tourist Office and city tourist information offices in Frankfurt distribute an informative 76-page booklet called "Gut Essen ... Eats & Treats in Frankfurt am Main." The guide describes dozens of restaurants and lists them under categories such as "tops in quality and price," "fine and distinguished," "small but fine" and "cheap and tasty." Included are numerous wine taverns in Sachsenhausen. A locater map also is provided. INFORMATION: German National Tourist Office, 747 Third Ave., New York, N.Y. 10017, (212) 308-3300.