John William Burgon's "rose-red city half as old as time" is one of Jordan's great treasures. While it gained a small amount of fame through association with the popular 1962 film "Lawrence of Arabia, the city's stunning architecture and unique water management methods made it a marvel far before the film. The city was carvedinto the slope of Mount Hor sometime in 6th century BCE, and was fought over by the Romans, King Herod, and even Cleopatra. With a grand theater, their own coinage, and a nearly unassailable fortress, the capitol city of the Nabatean empire was a feat well before it's time. Today it is a UNESCO World Heritage site and listed by the BBC as one of "40 places to see before you die".

Basilica Cistern

Just a stone's throw from the Hagia Sofia (and a couple stories down) lies one of the most impressive wonders of Istanbul.Built sometime around 6th century CE, the structure was a large basilica involved in commerce and the arts. It was later converted to a cistern during Emperor Justinian's reign to store water for the palace - capable of holding almost 21 million gallons of water. Scholars still haven't figured out all of the repurposed temple's secrets: a pair of odd Medusa heads (one upside down, the other on it's side) grace the bottom of two pillars. Is their positioning to ward against evil spirits, or just to allow the pillars to fit correctly? James Bond also made a brief rowboat trip through the cistern in From Russia With Love.

Coober Pedy

The Australian Outback has some brutal living conditions, and much of the country is uninhabitable by humans. In Coober Pedy, the scorching heat would scare off almost any settler - except for the presence of a huge lode of opal in the area. Residents avoid the over-100F temperatures by living in "dugouts" carved into the hillsides, which allow for more reasonable temperatures. Above ground, the near-wasteland has been used in such films as Mad Max Beyond Thunderdome and Pitch Black. The residents have a good sense of humor about their situation - artist Claus Wirris created the town's only "tree" out of scrap metal atop a hill in the town.

Moscow Metro

The Moscow Metro is not the highest-volume underground tranportation system - that honor goes to Tokyo. However, the pre-WWII system is one of the most stunning underground structures of any kind. Stalin himself pushed for a "radiant" style, including high ceilings, marble walls, gold anodized lamps, and iconic chandeliers of copper, blue ceramic, and milk glass. 2.3 billion passengers take the Metro each year, and while many other countries are used to exposed cement and grimy ceilings, the Muscovites are still riding in style.

Derinkuyu

The most famous of four major underground cities, Derinkuyu is one of the wonders of ancient Cappadocia. One of the oldest and largest underground structures, Derinkuyu's massive depths (reaching eleven seperate levels) could hold some 40,000 people with their livestock and belongings included. Likely created as a means for Christians to hide from persecution, the city included a chapel among its many amenities, as well as massive stone doors to secure each level. The cave-dwellers even went so far as to establish travel options - a tunnel connects the massive underground complex to Kaymaklli, another underground city.

Metropolitan Area Outer Underground Discharge Channel

There is little glamorous about the function of this Kasukabe overflow control channel - it simply functions to prevent floods in Tokyo. But given the presence of tsunamis and other hazardous water possibilities, this structure is one of the largest in the world, and can pump out 200 tons of water per second. The main attraction for visitors is the "Underground Temple" - the main water tank's stunning pillars easily dwarf the viewer. A Range Rover commercial featured the car driving inside the massive structure.

Salt Cathedral

The Salt Cathedral of Wieliczka, Poland is fairly literal in its etymology. A former rock salt mine, the cathedral carved out by the miners for daily prayers was ultimately expanded and turned into a tourist attraction, continuing on after salt production ceased in 1996. Counting Goerthe, Chopin, Pope John Paul II and Bill Clinton among its visitors, the site has been a UNESCO World Heritage site since 1978. In addition to a stunning underground lake, the cathedral prominently showcases its namesake material - several of its statues and even the chandeliers are made of raw or reconstituted rock salt.

Kish

Another ancient aquaduct, the underground city on the island of Kish showcases their Kariz - underground water storage facilities essentially similar to the cisterns of Europe. The small waterways of the Kariz can be traversed by boat tour, and the masonry is supplanted by stunning coral in several areas. The island is also a free trade zone, and several investors have planned future renovations and commercial expansions to the 1,000-year-old site.