The massive, incredibly rare instrument is over 11 feet tall with a range so deep it goes lower than humans can hear.

One of the final grand railway depot hotel complexes is slowly being restored to its former glory.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

Stairs often replace streets on the steep slopes of this old mining town.

A geological mystery on Camelback Mountain.

The highest point in Arizona is an oddly snow-topped peak within the otherwise arid state.

A wild west cemetery in Tombstone, Arizona, provides a window into the Old West.

Ancient pueblos built into the base of a natural canyon wall.

A spiritual vortex among the red rocks in Sedona.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

Limestone caves with spectacular showcase chambers.

An urban laboratory.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

See massive fossils that are over 200 million years old in northeastern Arizona.

A reproduction of earth's many biomes.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

A theatre built to house the rowdy Oxford graduation ceremonies became the stage for a debate about God's existence.

The beams of the New College, Oxford dining hall come with an amazing story.

Oxford University's stateliest library seems designed to make students truly feel the weight of knowledge.

One of Europe's oldest libraries.

Home to the most complete dodo remains known - one head, and one foot.

Ancient Egyptian wigs, South American feather headdresses, a bounty of anthropological artifacts in Oxford.

Used as an example in one of the first dictionary entries for "museum" in 1706.

One of the largest underground systems runs under Canada's largest urban center.