how many stair cases does it have?
Two spiral stairs.
Washington Monument
So the large landing at the 490-foot level was expanded to a full floor and the original spiral stair in the northeast corner between the 490- and 500-foot levels was replaced by two spiral stairs in the northeast and southeast corners. Now visitors exit the elevator on the observation floor, then walk down either spiral stair before reboarding the elevator for their trip back down.

who was president when the washington monument was built UNANSWERABLE when was it built? Construction began in 1848. when did it get completed? 1888 who built it? Robert Mills was the architect. did he also design it? Yes, the society held a competition for designs, and he was the winner. who inaugurated it? Chester A. Arthur who was he? He was  an American attorney and politician who served as the 21st president of the United States from 1881 to 1885. where is the monument located? On the National Mall in Washington, D.C. which country? United States of America who was the monument named after? George Washington was he a president? Yes, he was the first president of the United States. who financed the construction of the monument? UNANSWERABLE was it damaged by any natural disaster? Yes, it  sustained damage during the 5.8 magnitude 2011 Virginia earthquake. what material was used to build it? Marble, aluminum what kind of security protects it? Visitor screening facility. how tall is the monument? UNANSWERABLE
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Washington Monument [SEP] Stairs and elevator
The four supporting the elevator extend from the floor of the elevator pit to above the observation floor and were set at the corners of a square. The weight of the ironwork is . Cast iron, wrought iron, and steel were all used. The two small spiral stairs installed in 1958 are aluminum. Most landings occupy the entire east and west interior walls every 10 feet from and including the east landing at the 30-foot level up to the west landing at the 480-foot level, east then west alternately. Three stairs with small landings rise from the entry lobby floor to the 30-foot level successively along the north, west and south interior walls.