Henry David Thoreau lived for two years at Walden Pond near Concord, Massachusetts in the 1840s. He built a small cabin on land owned by his friend and mentor Ralph Waldo Emerson. During his time at Walden Pond, Thoreau observed and studied nature, seeking a simple life focused on contemplation. He interacted with some local workers and received occasional visitors. Thoreau used his time at Walden Pond to write and develop his ideas about living simply and self-reliantly in nature. He returned to civilized life in 1847, having gained insights that he would later publish in his famous book Walden.