Tallest tree living
Who
Hyperion
Where
United States Redwood National Park
When

The tallest tree currently growing is Hyperion, which measured 115.54 m (379.1 ft) in September 2006. This coast redwood (Sequoia sempervirens) was discovered by Chris Atkins and Michael Taylor (both USA) in the Redwood National Park, California, USA on 25 August 2006.

The initial measurement read a height of 115.24 m (378.1 ft), however it was measured again by Dr Steve Sillett, Mike Taylor, Chris Atkins and Robert van Pelt by climbing it and dropping a tapeline.
Remarkably, Hyperion is situated on a hillside (not alluvial flat), 96% of the surrounding area of which has been logged of its original coast redwood growth.

Atkins and Taylor had just earlier (1 July 2006) discovered two other coast redwoods in the same park, both of which also beat the previous holder, Stratosphere Giant. Their initial measurements concluded that: Helios measured 114.69 m (376.3 ft) and Icarus, 113.14 m (371.2 ft).