There are colonies of clonal trees that have lived for tens of thousands of years, but there's something majestic about a single tree able to stand on its own for millennia. These ancient trees have bore witness to the rise and fall of civilizations, survived changing climates, and even persevered through the fervent development of human industry. They are a testament to the long view that Mother Nature takes in tending the Earth. With that in mind, consider the world's 10 oldest living trees.