Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

An urban laboratory.

This rustic cabin, outfitted with gun slits, was once home to John D. Tewksbury, patriarch of the bloodiest family feud in American history.

Once a year, at exactly 11:11 a.m., this monument comes to life.

A geological mystery on Camelback Mountain.

A towering bronze statue memorializes the founding father of postwar American conservatism.

A tunnel of hardened lava along Maui’s famous Road to Hana.

Crouch down, stretch tall, and be sure to flail your legs to pay homage to the Monty Python classic.

This Rhode Island mansion was a stand-in for the exteriors of Collinwood in the original "Dark Shadows" series.

Three and a half miles of cliffs, rocky beaches, Gilded Age mansions and 40 Steps to nowhere in particular.

Oldest synagogue in the United States.

You can spend the night as an honorary lighthouse keeper in this quaint, historic beacon.

A 60-room castle constructed by a horse-racing heir.

Tubing through a cave lit with glowworms is a magical underground experience.

A once-glowing grotto at the bottom of Waikapalae Wet Cave.

An exotic wildlife habitat right off The Strip.

An overlooked monument to the celebrity gangster who helped put the sin in Sin City.

On top of a sheet metal business in Juneau stand nearly a dozen charming Wizard of Oz statues.

A tiny wilderness cemetery commemorates the deadliest episode of the Klondike Gold Rush.

The facade of this relic from the Klondike gold rush is decorated with over 8,800 pieces of driftwood.

A classic gold rush hotel can be expected to pick up some ghosts along the way, and the Golden North is no exception.

A historic freight system that found the true gold rush is in tourism.

A monument commemorating the role of Alaska's native Tlingit guides in the Klondike Gold Rush.

A whale of a public art display towers atop Juneau's cruise ship dock.