Philadelphia's Fairmount Park bills itself as the largest landscaped urban park in the world, its contiguous 4,077 acres snaking out from Center City along either side of the Schuylkill (pronounced "SKOO-kill") River.

The park, in fact, is the "skewer" around which the northwestern section of the city is built. It provides easy-access escapes from urban life, with its lush foliage and secret trysting spots, winding creeks, a covered bridge and bike paths. And its restored buildings are classic examples of architecture dating from the 17th to the early 19th centuries.

But the incredible variety of sculptures -- hundreds of them scattered throughout the park -- is perhaps the most impressive and engaging aspect of the park. The first was installed more than a century ago; and today, new sculptures are acquired regularly and the placement of other works is constantly reevaluated. park serves as a backdrop for these varied works, a flexible, alfresco sculpture museum in which the pieces must adapt to a setting that changes every day and every season.

The works vary from the very famous -- such as Frederic Remington's "Cowboy" -- to popular favorites such as Auguste Rodin's "The Thinker" to relatively unknown gems, including John J. Boyle's "Stone Age in America." But the placements are often as important, and as varied, as the works themselves: They nestle near bushes, perch upon crags, line both sides of the Schuylkill River like sidewalks along a street, pepper niches in and near the Philadelphia Zoo and herald entrances to buildings.

The sculptures weave in and out of your experience of the park, persistently popping up when you might least expect them. You might ride your bike past a Milles, or stroll by a Calder, or drive near a Nevelson. All in all, the integration of natural and man-made beauty makes for a delightful springtime escape.

BAT10 Although some works are hidden in the recesses of the park and only stumbled upon by unsuspecting meanderers, there is a fairly comprehensive route that takes in many of the major sculptures. It is no more than 15 miles long, and it makes for an ideal bike ride. (You can drive the route, but you won't always find parking near the works you want to see.)

The route starts at the Swann Memorial Fountain at Logan Circle in Center City (officially a part of Fairmount Park), heads northwest up the Benjamin Franklin Parkway, past the Rodin Museum, to the Philadelphia Museum of Art. It continues north up along the Schuylkill River on Kelly Drive (formerly East River Drive) to the Falls Bridge, and then heads back down along the other side of the Schuylkill on West River Drive, with optional detours to see the sculpture at the Philadelphia Zoo and Memorial Hall.

This sculpture tour is enhanced by the seasonal changes in foliage and by the presence of university sculling teams practicing on the Schuylkill.

For pedestrians, many of the sculptures are within an easy walk from Logan Square to the Museum of Art and just beyond. These include Alexander Stirling Calder's "Shakespeare Memorial," with Hamlet and the jester Touchstone, and Paul Manship's "Aero Memorial," a celestial sphere that's a memorial to the aviators who died in World War II, both at Logan Circle; Jacques Lipchitz's powerful "Prometheus Strangling the Vulture," on the east terrace of the art museum; and the gilded bronze "Joan of Arc" by Emmanuel Fremiet, striking in its noble stance, located where Kelly Drive begins at the art museum.

Perhaps the most popular sculpture in the park is Frederic Remington's "Cowboy," the artist's first -- and last -- large-size bronze work, installed in 1908, a year before he died. Perched on a rocky crag right along the busy Kelly Drive, the sculpture is a romantic "stop action" study of a rough-and-tough cowboy astride a horse that apparently has just halted at the edge of a precipice after galloping at top speed. The sense of suddenly stopped motion is captured in the horse's outflung foreleg and windswept tail. cowboy was Remington's friend, Charlie Trego, a native Pennsylvanian who, appropriately, later became manager of "Buffalo Bill's Wild West" show, an exhibition that featured cowboys and Indians and toured for many years in this country and abroad, beginning in 1883.)

A common complaint about this much-loved sculpture is that it is inaccessible, both visually to the commuters who whiz by it on their way in and out of Center City, and to any pedestrian who risks an accident crossing Kelly Drive to get to it. But because Remington chose the location -- at that time, Kelly Drive was just a dirt path with little traffic -- there's little chance the sculpture will ever be moved.

Another favorite is Alexander Stirling Calder's "Swann Memorial Fountain," in the center of Logan Circle, where 19th Street and Benjamin Franklin Parkway intersect. (The parkway is a visual gem itself, having been modeled after the Champs E'lyse'es.) Three allegorical nude figures represent the three waterways -- the Schuylkill River, the Delaware River and Wissahickon Creek -- that surround Philadelphia, and the fountain was named not for the swans that are part of the sculpture but because it is a tribute to a Dr. Wilson Cary Swann, founder and president of the Philadelphia Fountain Society.

This work was initially criticized because it was felt that many visitors wouldn't understand the symbolism of the allegorical figures. Still, when it was dedicated in 1924, 10,000 people danced the tango to the music of the police band.

Not far from the Swann fountain is Auguste Rodin's tremendously popular "The Thinker." Pondering his fate, head in hand, right in front of the delightful Rodin Museum on the Benjamin Franklin Parkway, "The Thinker" also was frowned upon when it debuted in Paris in 1880. It was regarded as only a larger version of the sculpture that dominates the tympanum of Rodin's "The Gates of Hell," a bronze cast of which also stands at the entrance to the Rodin Museum.

"Public art doesn't inspire unanimity of taste," says Penny Balkin Bach, executive director of the Fairmount Park Art Association, a private agency that commissions, purchases and places sculpture in the city in coordination with developments in urban planning. "It doesn't quietly and comfortably get to where it is, and is often very controversial in the beginning." But Philadelphians sooner or later "come around," and their favorite works now are those that have long been highly regarded in the art world.

Yet this is a city that also takes chances, and displayed Claus Oldenberg's "Clothespin," Robert Indiana's "Love" sculpture (made famous on a U.S. postage stamp) and, only last year, Isamu Noguchi's "Bolt of Lightning," a work on which the jury is still out. BAT10 But then there are the sculptures that are well known because they aren't well liked. Probably one of the least popular is "The Young Mehert," by Khoren Der Harootian, prominently displayed at the base of the Philadelphia Museum of Art, next to the entrance to Kelly Drive. A gift of Philadelphia's Armenian community, the sculpture depicts a soldier holding a sword that apparently is aimed at himself.

"Everyone thinks it must be really important because of where it is, but they want to know, 'Why is this man killing himself in front of the museum?' " says Bach.

Her own favorite is "Stone Age in America," by John J. Boyle, installed in 1887. A small work that is impressive in its sensitivity and strength rather than in any splashy presentation, it shows an Indian mother determinedly defending her children from an anticipated charge of a bear, a hatchet in her right arm, her baby in her left. A dead cougar lies at her feet, its head falling over the base of the sculpture.

"Stone Age in America" recently was spruced up after having been vandalized and moved from Sweetbriar Mansion, deeper in the park, to a more prominent spot near the Ellen Phillips Samuel Memorial on Kelly Drive. The Samuel Memorial, which extends a short distance along Kelly Drive, consists of the works of 16 sculptors whose pieces symbolize American history. They include the ensnarled power of "Spirit of Enterprise," by Jacques Lipchitz, the more traditionally inspiring "Welcoming to Freedom," by Maurice Sterne, and Henry Rosen's "Quaker" and "Puritan," representing the forces of statesman and soldier which, together, formed America.

"The Washington Monument" by Rudolf Siemering, in front of the Philadelphia Museum of Art, is another favorite -- thankfully so, since it took more than 80 years to take this work from idea to fruition (16 of them devoted just to casting the bronze figures on it). The monument, completed in 1897, is divided into three levels: Washington, the hero, on a horse, on the top level; Washington's era (depicted by friezes and groups of sculptures) in the middle; and at the bottom, his country, represented by animals indigenous to North America.

Other sculptures in Fairmount Park seem to be imbued with no more meaning than the inherent joy of the works themselves. Carl Milles' delightful trio of "Playing Angels" sits on high concrete bases along Kelly Drive, and is visible for miles. These agile musicians are second casts from a group of five originals at Millesgarden, the outdoor sculpture garden in Stockholm.

The Philadelphia Zoo in Fairmount Park also features some wonderful works, including Edward Kemeys' visceral "Hudson Bay Wolves." Completed in 1872, the bronze -- depicting the moment at which wolves begin to fight among themselves for the deer they have just killed -- was the first work commissioned by the Fairmount Park Art Commission. A masterpiece of musculature and illustration of "the moment," it stands adjacent to the zoo's Wolf Woods.

Both Albert Laessle's playful "The Penguins," at the entrance to the Bird House, and the highly strokable "Bear and Her Cub" by Joseph J. Greenberg Jr., near Bear Country, are similarly well placed. Both are solid, dense works, the total opposite of the airy Impala Fountain by Henry Mitchell, in which a dozen skeletal animals leap gracefully over water.

Placement of works changes in the zoo, as well as outside. The ferocious "Lioness Carrying to Her Young a Wild Boar," by Auguste Cain, used to terrify approaching horses and so was moved from the River Drive to the zoo (where it no doubt terrifies young children).

But a short walk after entering the main (north) gate of the zoo is the sweetly maternal "Cow Elephant and Calf." When it was completed by Heinz Warneke in 1962, the 37-ton work was the largest free-standing sculpture in the United States carved from a single piece of solid granite.

The family theme is continued, with a major variation in mood, in front of the sameentrance to the zoo, with Wilhelm Franz Alexander Friedrich Wolff's moving "The Dying Lioness," showing a lioness in the throes of death surrounded by her hungry, uncomprehending cubs and, above her, the grieving lion. The work, completed in 1873, was first exhibited at the Centennial Exhibition in Philadelphia in 1876.

The nearby Memorial Hall, at 42nd Street and Parkside Avenue, is the only major building remaining from that exhibition and is the general location of several noteworthy sculptures.

The two Pegasus sculptures in front of Memorial Hall were originally created by German artist Vincenz Pilz for the Vienna Opera House, but the Austrian government believed they were out of scale and returned them to the foundry for melting, where they were rescued by Philadelphian Robert H. Gratz.

Nearby is Alexander Milne Calder's 1887 equestrian sculpture of Maj. Gen. George Gordon Meade, who was one of the first commissioners of Fairmount Park. Calder knew Meade, a Union general who turned back Confederate forces at Gettysburg. It took nearly 10 years for Philadelphia to raise the money for this sculpture, and creative fund-raising methods included "Meade Memorial Matinees" at the Walnut Street Theater.

Also near Memorial Hall is J. Otto Schweizer's 1934 piece, "All Wars Memorial to Colored Soldiers and Sailors." It is one of a few sculptures in the park either created by a black artist or portraying black characters. In fact, a recent -- and controversial -- proposal to create a separate black history sculpture garden at the Belmont Plateau section of Fairmount Park is now being debated.

Other noteworthy public art in Fairmount Park includes: the Art Deco facade of the Fidelity Mutual Life Insurance Co., whose sculptural ornamentation was created by Lee Lawrie, across Pennsylvania Avenue from the Art Museum; "Atmosphere & Environment, XII" by Louise Nevelson, a vertical steel work at the west entrance of the Museum of Art, right near Jacob Epstein's "Social Consciousness"; "Abraham Lincoln," by Randolph Rogers, which shows a seated Lincoln because the president would have sat to sign the Emancipation Proclamation (regarded by Rogers as Lincoln's most important act), elevated at the beginning of Kelly Drive; "Thorfinn Karlsefni," by Einar Jonsson, a bronze of the 11th-century Icelandic explorer, at Boat House Row on Kelly Drive; and "General Ulysses S. Grant," by Daniel Chester French and Edward C. Potter, an equestrian statue, located further up Kelly Drive.

And while you're scouting out sculpture in Philadelphia, you might expand your search to other locations in the city, especially those known for unusual works: Penn's Landing, with its sculpture of the sacred bull Nandi, the largest Nandi outside India; the Grand Stair Hall in the Philadelphia Museum of Art, with its sculpture of the goddess Diana, originally on the tower of the old Madison Square Garden in New York City; and City Hall, with its 250 figurative sculptures on the building's interior and exterior, and also that much-loved 27-ton statue of "Billy" Penn.