At the Mountains of Madness – H.P. Lovecraft

"Tekeli-li! Tekeli-li!"

An Antarctic expedition from Miskatonic University discovers a mountain range higher than the Himalayas and the frozen remains of life-forms that predate humanity by millions of years. As they explore a cyclopean city hidden behind the mountains, they uncover the history of the 'Elder Things' and the terrifying Shoggoths that destroyed them, realizing that they have awoken a danger that could threaten the world.

Lovecraft's science fiction horror novella is a masterpiece of world-building. It blends scientific exploration with ancient mythology, suggesting that the history of Earth is far older and stranger than we dare to imagine.