The Washington Square Arch is a marble triumphal arch located in Washington Square Park, Greenwich Village, Manhattan, New York City. It was designed by architect Stanford White in 1891 and completed in 1892 to commemorate the centennial of George Washington’s 1789 inauguration as the first President of the United States. Its a key cultural meeting spot in the city.
 
Interesting facts...
Its not the first.The original arch was a temporary wooden structure erected in 1889, but its popularity led to fundraising for the permanent marble arch designed by Stanford White.
Hwn they stareted to build they found a grave on the site.