Seth Bullock, the sheriff of Deadwood, built this town immediately after Teddy Roosevelt’s death in 1919.

Every president in history is immortalized in bronze in downtown Rapid City.

One of America's first dinosaur parks gives a window into Depression-era paleontology.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

Hidden behind Lincoln's head is a chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

Considered by many to be one of the most dangerous highways in Alaska.

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

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Constructed on the ruins of a convent, this tower saved countless lives.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

The king of U.S. high points towers over every other peak on the continent.

A plaque marks the spot where the saint was shoved off the Charles Bridge and into the river.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

This doorless 20th-century elevator doesn't stop or slow down.

This artificial cave looks like something out of a fairytale.