You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

For over 70 years, this house was home to a pioneering Black artist and educator.

Through the decades, Black music stars have performed at this historic hub for music and the arts.

This poor little statue is the most vandalized memorial in Washington.

America's greatest forgotten garden and the former stomping grounds of Son of Sam.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

Modern art meets modern convenience in possibly the world's most architecturally important public bathroom.

An off-the-beaten-path place to literally hang beneath Milwaukee's Holton Street Bridge.

The spaceship-like theater, which is still in use, was one of the most popular exhibits at the 1964 New York World's Fair.

Isak Heartstone, a 15-foot wooden troll made out of recycled materials.

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

A cemetery that holds graves for the forgotten children of a burned orphanage.

Whimsical artist house in the New Jersey woods.

One of the U.S. Forest Service's only mansions is outfitted with a dinner table for floating food.

The highest point in New Jersey is marked by a massive, if simply named, obelisk.

A winding, cliffside stretch of road overlooking the Delaware River.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

An encyclopedic collection of mammal penises.

One of the oldest family businesses in Reykjavík serves lamb-based hot dogs.

A colorful architectural gem in Seattle's uniquely modern Central Library.

Walking by this fence is like strolling along a portal to various fictional worlds.

A bike being "eaten" by a tree is the real Vashon legend behind popular children's book, "Red Ranger Came Calling."

A seven-story 1920s mausoleum outside Denver houses thousands of remains.