Randall Munroe has posted a chart comparing the earth's holes at xkcd. There's a lot of information, so you will want to see the full-size version here. This might remind you of the ominous depth comparison video from a few years ago, but here you can see how these holes compare next to each other and to sea level. You'll notice some holes that are pretty deep start at higher elevations, and the Jinping Laboratory in China has an impressive hole that doesn't go down at all. The word "oops" made me go look up the Retsof Salt Mine, which has a wild story. We knew Lake Baikal in Russia is the world's deepest lake, but the sediment underneath indicates it was once much, much deeper. But not as deep as the Kola Superdeep Borehole. It's amazing that we have two manmade holes that are deeper than the Mariana Trench. 
If any of these locations pique your interest, there is information and links for each of them at Explain xkcd. -via kottke
Commenting on Neatorama will earn you NeatoPoints!