Height of Pyramidion 55 feet

Thickness of Walls at Base 15 feet
Thickness of Walls at Top 18 inches
Thickness of Pyramidion Walls 7 inches
Outside of walls covered with white marble from Maryland.

Inner walls set with 189 carved memorial stones donated by individuals, societies, cities, states, and other countries.

Number of Steps to Observation Deck 898

Designed By Robert Mills
Cornerstone Laid July 4, 1848
Laid with same trowel used by George Washington to lay cornerstone of the Capitol.
Actual Construction Begun August 17, 1880
Construction Completed December 6, 1884
Dedicated February 21, 1885
Opened to the Public October 9, 1888

Total Cost $1,187,710.31

Official Website www.nps.gov/wamo