The high and rugged Sierra Nevada mountains located behind the Great Basin Desert east of California, extensive forests and mountains in the north, the rugged and harsh Sonoran Desert and Mojave Desert in the south and the Pacific Ocean on the west effectively isolated California from easy trade or tribal interactions with indigenous populations on the rest of the continent, and delayed the tragedies and damages of colonial-settler arrival until the Spanish missions, the Gold Rush, and the Euro-American invasion of indigenous Californians' territories.