The platform atop this verdant volcano was built with the help of a royal elephant.

A New Zealand communications tower stands as the tallest structure in the Southern Hemisphere.

Experience a quartz crystal sound bath inside a storied, all-wood sound-chamber.

This impressive Boston holy house is the American mecca for Christian scientists.

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

San Francisco's newly reopened hands-on science museum.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The world's longest known cave system.

Tubing through a cave lit with glowworms is a magical underground experience.

Home to items never before seen by the public.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A mysterious castle built as a monument to lost love.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

The first declared National Monument in the United States.

The only theatre in the world constructed specifically for sound movement.

Two stunning 17th-century libraries and a cabinet of curiosities.

Try not to get slimed in Tribeca.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

Macabre astrological automaton clock dating to the late 1400s.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.