petroleum geology
I remember finding out about the Tethys Sea and being really excited. I was just beginning my studies of Old World prehistory, Africa, and Human Evolution. What I learned about was the remnant sea separating Africa and Eurasia called Tethys, though it is much more than that (see below). Imagine a Eurasia with no Alps, no Caucasus, and no Arabian Peninsula. Much of southern Europe and huge swaths of North Africa are underwater, and Africa is so far away from Eurasia that all the classic seas of the region don't exist simply because they are part of the ocean. If you were in the western…