The nonprofit in charge of development along central Philadelphia's Delaware River waterfront is preparing to tear down the towering cement monolith near Penn’s Landing’s Great Plaza amphitheater that was built almost two decades ago to anchor an ill-fated tramway to Camden.

In an emailed solicitation Tuesday, the Delaware River Waterfront Corp. said it is seeking bids from contractors to demolish the tram tower, an iconic piece of unused urban infrastructure that has compared to a turn-of-the-21st-century Stonehenge.

"It's the end of an era," said Harris Steinberg, who led a committee that 12 years ago helped envision what's now the waterfront's master plan.

The tram proposal, envisioned to transport 3,000 people an hour between shopping-and-entertainment complexes on either side of the river, was indicative of the capital-intensive economic-development proposals that had been in fashion since the 1970s, he said.

"The tram was the last dying gasp of the big-bang development era," said Steinberg, now executive director of Drexel University's Lindy Institute for Urban Innovation.

DRWC president Joe Forkin was not immediately available to share details of the solicitation, which also seeks bids for constructing the walking and cycling trail planned along Columbus Boulevard between Washington Avenue and Spring Garden Street.

The request for demolition bids also comes as the agency completes engineering and design work for a four-acre park that would cap a portion of I-95 between Chestnut and Walnut Streets, just south of where he tram tower stands.

The arch-shaped tower and a South Jersey sibling were built in 2002 as part of a plan championed by former Mayor Ed Rendell involving a complex that was to have been built by mall developer Simon Property Group with a historic carousel, the Please Touch Museum, and a Cheesecake Factory restaurant.

But after the tower was built — at what is said to have been a cost of some $16 million — Simon pulled out of the plan, leaving each side of the Delaware River with its own useless vertical slab.

The Penn’s Landing tower "really became part of the public consciousness as a totem of the past and the present,” Steinberg said. “It’s almost like a piece of the Berlin wall.”