Mt. Everest and the Himalaya Mountains were once sea floor on the northern edge of the Indo-Australian Plate. As that plate moved north, it collided with the Eurasian Plate. The two plates crunched together, forming the Himalaya, Pamir, Hindu Kush and other mountain ranges in the region. In fact the Himalya are still rising. The rock that was once sea floor rose up over a period of about 30 million years, and brought all the fossils with it.