The only surviving piece of Copenhagen's 16th-century defensive wall.

The gilded, masterful astronomical clock will calculate time, dates, and planetary positions for thousands of years to come.

This pair of gilded girls atop an Art Deco building in Copenhagen were built to function as a weather indicator.

A Hawaiian stairway to heaven—that you can't climb.

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

This former luxury resort in Kaua'i is now an abandoned relic.

Now a pedestrian bridge, this was once part of a narrow-gauge railroad that ran along the east coast of Kauai.

A unique collection of Western and Japanese-style graves.

In 2018, Pohoiki Road was severed by lava flowing from the eruption of Kilauea.

Ten acres of the Kula Forest Reserve make up this wondrous state park.

Images chiseled into the basalt here date back an estimated 300 years.

This ruined fort and statue are a testament to the last king of Kaua‘i’s savvy diplomacy skills, which briefly brought Russians to Hawai‘i.

Formerly a lovely white sand beach this Hawaiian stretch is now a trap for countless tons of trash.

This tiny Hawaiian island is slowly coming back to life after being bombed during naval training exercises.

Once home to over 8,000 exiled Hawaiians suffering from Hansen's Disease.

A controversial memorial at the place where Captain Cook met his violent end.

The southernmost point in the United States is a beautiful place to look at but a deadly place to wade in.

This unusual lava tube spouts seawater during high surf.

This narrow coastline trail through the dense Kauai wilderness is among the most beautiful and dangerous in the world.

Take shelter from Hawai'i's tropical heat under the massive canopy of largest Banyan tree on the island.

This blowhole is supposedly caused by a trapped monster.

A cooled lava flow from the Haleakalā volcano formed these surreal-looking columnar basalt structures.

Submerged lava formations create incredible waterworks.

A prehistoric landscape hidden in the cliffs of Maha'ulepu.