Volcanic activity causes small pools of super-heated mud to boil furiously.

The youngest volcano in Central America.

An intentionally grounded cargo ship remains half-buried in the sand.

This wildlife refuge is home to more than 200 species of birds, as well as monkeys, lizards, and other wildlife.

This Costa Rican chapel is the most metal church in the world, literally.

The translucent turquoise hue of these natural swimming pools comes from a high concentration of minerals.

In Costa Rica's cloud forest, the roots of a woody ficus create a botanical bridge.

This abandoned hospital is one of the most haunted places in Costa Rica.

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

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

The sister plane of the C-123 shot down during the Iran-Contra Affair has found a new purpose in retirement.

These mysterious ancient stone spheres were created by a civilization lost to time and are now mostly lawn ornaments.

Once the foundation for a mansion, these ruins now offer amazing panoramic coastal views.

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

This Costa Rican topiary park is a surreal garden of unearthly delights.

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

This 17th-century fort, built by the Dutch to control a piece of the international spice trade, is now a city park.

A striking series of six bridges connect islands in Indonesia.

Of five volcanoes located in the massive Tengger caldera, this cone is the youngest and most active.

One of Indonesia's tallest, this waterfall takes a 390-foot plunge into the Lake Toba caldera.

Mount Tambora is the site of the largest and deadliest volcanic eruption in recorded human history.

One of the holiest places in the region, devotees come to Tirta Empul to bathe in the holy spring water.

This mile-wide crater high in the mountains of Indonesia is the largest gold mine in the world.

An Indonesian mosque styled after St. Basil's Cathedral.