At more than 3,000 years old, this ancient European yew growing behind a churchyard wall in the village of Fortingall in Perthshire, Scotland, is believed to be the oldest tree in the United Kingdom and possibly in all of Europe. The tree's other claim to fame is its recent sex change. For as long as anyone remembers, this long-lived treasure has been male, but recently scientists from the Royal Botanic Garden in Edinburgh discovered three red berries growing on a branch of its outer crown. Berries are only found on female yews, and the switch may be due to environmental stress. Of course, the rest of the tree remains male, making it one of the most unconventional trees you're likely to see.