A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

This former coal gasification plant found a curious second life as a popular public park.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

In 2010, Nicolas Cage purchased two plots in this cemetery using one to construct this strange pyramid mausoleum.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

Quite simply the largest tree in the world (by volume).

This quirky curiosity shop takes its cues from the world's bazaars.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

This semi-secret garden in south Seattle emulates a traditional Japanese garden using the plants of the Pacific Northwest.

The rocks in this arid basin leave trails of movement behind them.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

A self-built castle made by a mysterious man.

The "Seinfeld" diner.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

A walk through the historic city center, under the streets of Seattle.

A giant Troll lurks under one of Seattle's oldest bridges.

Try not to get slimed in Tribeca.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

A collection of old shoes in the middle of nowhere.