It covers lost civilization locations such as the 11,000 year old Gobekli Tepe site in Turkey (which I mentioned in my post Prehistoric Sophistication) and Knossos, which I feel may have once been a part of -- and possibly the capital of -- Atlantis.
More than that, it also goes into what could possibly cause the demise of once great civilizations that have been lost to time and become the things of legends. It cites examples of modern disasters such as the 2011 Japanese earthquake and tsunami that caused massive devastation and showed how mother nature can inflict destruction swiftly. Asteroids and climate change are considered as well.
It also questions whether entire civilizations can essentially be erased and forgotten by such disasters and if it's possible our own modern civilization could be erased in a similar fashion.
Definitely a good watch if your interested in the topic of lost civilizations or ancient and prehistoric history in general. You can watch the documentary below or get it from the History channel's website here. It's about an hour and half, so if you want to watch it and don't have time now, you can just click the little "watch later" clock button in the video on the bottom right and go back to it another time (this is especially useful if you have a way to watch it on your television, such as with the YouTube app on an Xbox 360).