This beautiful natural train tunnel is said to grant the wishes of visiting lovebirds.

A giant gun barrel in Barbados that once hoped to shoot outer space with science.

Underground hospital complex constructed by slave laborers during the German occupation of the Channel Islands.

A working model of the entire San Francisco Bay and much of the Sacramento River Delta, complete with regular tides that change every 14 minutes.

This unusual building straddles two countries.

The site of the climactic scene from the classic horror film is now a historic landmark.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

On Japan's Tashirojima Island, cats are king.

This immaculate and historic water garden culminates in a massive stone dining table with an inset fountain for chilling the wine of the Cardinal's guests.

San Francisco's newly reopened hands-on science museum.

The remains of a ruined mansion memorialize the 1906 earthquake.

Where the line between entertainment and aerospace blurs.

Collection of nearly 500 concrete figures sculpted by the late Veijo Rönkkönen.

Architecturally stunning library serves as the hub of Finnish scholarly life and culture.

The final resting place of a space program monolith.

This iconic Russian space museum sits on a landmark space production facility and houses the Vostok 1, the first manned spacecraft, that was also built here.

Moscow's imposing monument to the Space Age.

World's oldest and largest space launch facility, once a secret missile testing site.

Secret Soviet city once home to Russian cosmonauts and space training facilities.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

This pseudo-steampunk weapons facility is the world's largest wood and glue structure, and packs quite a wallop.

Cabaret where the show girls are all androids, and the patrons couldn't be more pleased.

A whimsical tower with a spiral staircase, inspired by the Space Age and the Möbius strip.

This unusually shaped mountaintop tower looks like a UFO floating over the city.