Composition of Earth's atmosphere by volume. The lower pie represents the trace gases that together compose about 0.038% of the atmosphere (0.043% with CO2 at 2014 concentration). The numbers are from a variety of years (mainly 1987, with CO2 and methane from 2009) and do not represent any single source.
User: How long did Thoreau live in the woods at Walden Pond? User: How long did Thoreau live in the woods at Walden Pond? Weegy: Thoreau lived in the woods at Walden Pond for two years, two months, and two days.
Ten years after Thoreau's death in 1862, in a spontaneous tribute to the writer and philosopher, visitors to the pond began placing rocks, flowers, and twigs in a cairn on a spot near where the house had been. The cairn became a standard stop for pilgrims to Walden.