Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

38-story baroque tower reflecting Detroit's rise, fall, and possible rise again.

The pieces in this sculpture garden are made from demolished buildings that were once landmarks of Motor City.

A wacky two-story folk-art assemblage of carved and found objects, with lights, motion, and sound now in need of financial support.

Opulent downtown movie theater now houses cars as an indoor parking garage.

One man's attempt to create an artistic wonder on a run-down block in Detroit.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

Look closely and you’ll notice that the color changes a third of the way up the tower.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

The walls of the iconic dome are hollow and have a secret stairway.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

A monumental statue of RCA's mascot now sits atop a historical society roof after a life of moving around.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

It's not hard to see why the historic Peabody Conservatory of Music's library has been described as a "cathedral of books."

The trials and tribulations of marking Poe's grave.

This elaborate towering structure was once famed for its revolutionary height.

Yo, Adrian!

A clone-tree in Washington Square Park sprung from seeds that went to the Moon and back.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

Huge masonic hall in Philadelphia with lavishly themed rooms.