Then there's the avenue's ambitious future. As you read this, a fine arts corridor is arising in the hardscrabble stretch between Girard and Lehigh avenues - and it looks like the dreamers behind this cockeyed notion might actually pull it off.

Meanwhile, a real-estate developer with optimism to beat the band is bent on resurrecting the retail strip under the El tracks in the Frankford neighborhood.

We'd laugh, but he's already rehabbed four buildings with downstairs retail space and upstairs apartments, transplanted a cadre of working artists to suddenly quaint Gillingham Street and attracted a classy restaurant/jazz bar.

Farther up the avenue, community leaders are looking to spark a Mayfair revival with the reopening of the Devon Theater, on Frankford between Robbins and Levick streets, as a 600-seat live-performance space. A new marquee, courtesy of Drexel University, is lighting the way, and planners hope to be programming live music and theater within about two years.

Whether it's the Fishtown/Kensington hipster scene or Civil War history that floats your boat - and we're talking gen-u-ine DNA samples from none other than Abraham Lincoln - the avenue has it.

Drugs? Prostitution? A motorcycle gang? In pockets, it has those, too - and we're talking a gen-u-ine Warlocks clubhouse. And soon to join that happy trifecta is gambling: The Delaware River site of the future SugarHouse Casino is where Frankford Avenue begins. But let's leave the vice to the vice squad and highlight the good stuff, since there's a lot of stuff along the 11 1/2-mile avenue that's secretly - sometimes shockingly - good.

The next "next Old City"

Frankford Avenue's most open secret is a new critical mass of hip destinations in Fishtown and Kensington for eating, shopping, art fancying, and (oddly) parking your bike.

As part of its push for a distinctive streetscape - and eventually, a full-blown arts corridor - the New Kensington Community Development Corp. recently commissioned local artists and metal workers to design bike racks that look like Pop Art sculpture, including a playful red construction at Frankford and Girard avenues by Fishtown's Robert Phillips, best known for the metal butterflies near the zoo.

"Some nights you'll go by and the bikes are just stacked up," says Yards Brewing Co. co-owner Nancy Barton, a Kensington community leader. "They're a sculpture themselves."

Among the pioneering businesses in this southern neck of Frankford Avenue are Ida Mae's Bruncherie (2302 E. Norris St., two short blocks off the avenue), a cute new restaurant where Irish breakfasts are the specialty of the house, Circle Thrift (2007-09 Frankford Ave.), with a good selection of retro clothes and household castoffs, and the Bicycle Stable, specializing in Bianchi bikes from Italy, including hipster favorites with "animal" saddles. (Decorated with a dashing stripe of faux leopard.)

Other hidden gems are sprinkled lightly among the rundown buildings and empty lots that still predominate here. To find them, pick up the helpful NKCDC's 2007 business directory, available at Rocket Cat Cafe (2001 Frankford) and some other neighborhood shops. It has a full list of who sells what, along with where to eat and drink.

This local treasure map also lists Fishtown and Kensington's many artists and artisans, including Phillips, the painter Mike Geno and the jeweler/bookbinder Minna Aaparyti

Most labor behind closed doors. "There are a lot of hidden workshops around here," says local businessman Michael Tonuci, of Michael's Decorators (2214 Frankford Ave.). But dozens will be part of the big Philadelphia Open Studios Tour this fall, if you're curious to see what goes on inside Frankford Avenue's boarded-over storefronts and converted factory buildings. Visit www.philaopenstudios.com for details.

Under the El

Further up the avenue, destinations are more spread out, and a car's a better way to get around than a bike. Or take SEPTA's Market-Frankford El to the Church Street station, where Frankford Avenue's important colonial history meets a small but sure gentrifying force of its own.

This area of Frankford Avenue, on and around the retail strip that's under the El in the Frankford neighborhood, was once the independent colonial town of Frankford, settled in 1660. At the time, Frankford Avenue was called the King's Highway.

Famous passers-by included William Penn, who traveled the road between Philadelphia and his summer place in Bristol, George Washington, who came through en route to his victory at Yorktown, and Paul Revere, who passed back and forth on the mail route he rode between Boston and North Carolina. "He rode this road many, many times," says Northeast historian Harry Silcox.

The Church Street stop has three important historic churches: the Presbyterian Church of Frankford (4301 Frankford Ave.), known as "the pink church" and designed by John McArthur, the architect who designed City Hall; Campbell AME (1657 Kinsey St.) 200 years old and known colloquially as "Second Bethel" and Saint Mark's Frankford (4442 Frankford Ave.), home to a 174-year-old Episcopal parish.