An enormous, inside-out glass globe built in 1935.

This picturesque medieval monastery guards a small trove of historic treasures.

An ancient knight and a symbol of the city's freedom.

A self-proclaimed libertarian micro-state on a tiny bit of disputed territory between Serbia and Croatia.

A tribute to an iconic act of defiance from the Croatian War of Independence involving a small car.

The now-overgrown beach resort was once frequented by Yugoslav military elite.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

Croatia's towering concrete blossom grows from the site of a World War II concentration camp.

This truly palatial work of Communist-era architecture now sits crumbling on a Croatian beach.

This huge metal monument is slowly being stripped to its concrete skeleton.

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

The remains of a sunken military ship wreck visible through clear water.

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

An ethereal glowing blue ocean cave in Croatia.

The youngest volcano in Central America.

Sloth rehabilitation center in the jungle of Costa Rica.

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

Disused penal colony features prisoner artwork, some sketched in human blood.

Costa Rican accommodation resembles a crash site, but with a nice balcony.

Where dogs like the rare "Fire-Tailed Border Cocker" run free on the mountainside.

This awkward aquarium sculpture is one of the strangest statues in Chicago.