A sequoia is a type of gigantic tree that grows naturally in a small area of California. These trees are among the tallest and most massive living things on Earth. The most famous sequoias, called giant sequoias, can grow wider than a school bus is long and taller than a 25-story building. Some have lived for over 3,000 years, meaning they were already ancient when the Roman Empire existed.

Giant sequoias grow in groves on the western slopes of California's Sierra Nevada mountains. Their thick, spongy bark helps protect them from wildfires and insects. Despite their enormous size, sequoias start from seeds smaller than a flake of oatmeal.

A related species, the coast redwood (sometimes also called a sequoia), grows even taller but not quite as massive. These trees thrive in the foggy forests along California's northern coast. The tallest known coast redwood stands over 380 feet high.

General Sherman, a giant sequoia in Sequoia National Park, is considered the largest tree by volume in the world. Standing beneath one of these ancient giants can make you realize how small humans are compared to the power and patience of nature.