@lucinternet: Mount Everest, the highest peak on Earth at about 8,849 meters above sea level, contains layers of marine limestone and fossilized sea creatures near its summit. These rocks formed hundreds of millions of years ago on the floor of an ancient ocean known as the Tethys Sea. Marine fossils such as crinoids and trilobites preserved in the rock provide clear evidence that the material originally formed underwater. The presence of marine rock on Everest is explained by the process of Plate Tectonics. Around 50 million years ago, the Indian tectonic plate collided with the Eurasian plate, pushing seafloor sediments upward to create the Himalayas. This geological collision continues today, which is why the mountain range is still slowly rising and experiencing frequent earthquakes.