what is united states capitol cornerstone laying?
It was the ceremonial placement of the cornerstone of the United States Capitol
United States Capitol cornerstone laying
The United States Capitol cornerstone laying was the ceremonial placement of the cornerstone of the United States Capitol on September 18, 1793. 
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United States Capitol cornerstone laying [SEP] Introduction
The United States Capitol cornerstone laying was the ceremonial placement of the cornerstone of the United States Capitol on September 18, 1793. The cornerstone was laid by president of the United States George Washington, assisted by the Grand Master of Maryland Joseph Clark, in a Masonic ritual. Many of the items of ritual paraphernalia used in the cornerstone ceremony have been repurposed and are currently used for the placement of foundation stones at other important buildings in the greater Washington area. Centennial and bicentennial observances of the U.S. Capitol cornerstone laying were held in 1893 and 1993, respectively, and a tricentennial observance of the ritual has been announced for 2093.