Two X-s visible on Elm Street mark the spots where the bullets struck President Kennedy. The Grassy Knoll was the location where unsuspecting Abraham Zapruder filmed the assasination that changed the history of the world. 6th Floor Museum; The Life and Times of John F. Kennedy is adjacent to the plaza at the corner of Elm and Houston Street.
First of all I was a little disappointed in the memorial. I don't know I guess I was expecting something different. I'm glad I went though. I went in the evening around 7 o'clock. it was dark and the area was pretty empty so I wouldn't suggest going in the evening unless you are with a group. And I think I would like to go back and see this in the daylight. Maybe I'd have a different perspective on the memorial itself and what it's trying to represent. The grassy knoll across the street also has a memorial on it. This is something free that you can just stroll in the area at your leisure.
The John F. Kennedy Memorial Plaza is free and open 24 hours a day. A block from Dealey Plaza, the memorial is easily reached from Union Station or West End Station. Created by architect Phillip Johnson (a Kennedy family friend) and dedicated in 1970, the memorial is surrounded by large concrete walls that appear to be floating. The memorial itself is a slab of black granite simply inscribed with the late president's name. It's definitely worth a quick visit during the day or at night when lit by floodlights.