Giant sequoia trees (Sequoiadendron giganteum). Giant sequoias are found on the western slopes of the Sierra Nevada Mountains in California at an altitude of between 1400 and 2400 metres. They reach 80 metres in height and 25 metres in circumference, making them the largest and most massive living thing on Earth. They are also the oldest, living for around 3200 years. Weighing up to 1.2 million kilograms, a sequoia is more likely to topple over before it succumbs to death from old age. Photographed in the Sequoia National Park, California, USA.