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

Found down a long dirt road, a sacred Mexican cenote and 18th-century hacienda remain hidden.

One of Mexico's youngest major cities still holds on to this structure representing its short modern history.

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

Inside this striking glass building, visitors can see thousands of dinosaur fossils in the positions that nature deposited them more than 150 million years ago.

A short boardwalk through a swamp leads to the spot from which the Louisiana Purchase was surveyed.

The final resting place of President Chester A. Arthur and hundreds of others from Revolutionary War soldiers to poets, politicians, and painters.

The only arched bridge made of stone on the entire Mississippi River.

This old residential building was once the largest flour mill in the world.

After the musical legend's death, his memorial was mysteriously graffitied in gold.

The 80-foot tire that looms over Michigan's I-94 was once a Ferris wheel in the New York World Fair.

A decaying concrete oil tanker served as a disposal location for bootleg hootch.

This unique shop is full of memento mori art, antique medical equipment, secret society paraphernalia, and historical relics.

Striking images of New Orleans history, including colonizers, soldiers, Klansmen, scientists, sharecroppers, and more, are depicted in frescoes that line the walls of this transportation hub.

After the oysters have been shucked, and the restaurant's been shuttered, the terrazzo sidewalk from the 1940s is all that remains.

The oldest operational cathedral in the U.S. has one shell of a way of projecting speakers' voices.

This cathedral dedicated to Louis IX, sainted King of France, holds many secrets.

Made of giant chains and hung with shackles, this iron cross honors those unknowns who perished under American slavery.

This New Orleans tree is filled with hidden chimes that produce a carefully tuned melody.

Colorful, cheeky signs spill out of legendary New Orleans folk artist Dr. Bob's Bywater studio warning you to "Be Nice—Or Leave."

One of the best-preserved Native American mounds remaining in the southern United States.

A castle-inspired apartment building that has stood in Birmingham since 1927.

They call this long foot bridge a swinging bridge, but really it's the bouncing you have to watch out for.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.