If you are looking for an observation deck in Los Angeles, the one at the top of L.A. City Hall is the best. The magnificent building feature a free, non-de script viewing platform overlooking downtown, the west, the south, and the north. After clearing security, take the elevator to the top floor. Once there, you have to go up one of two staircases to access the deck. It isn’t marked. Once up the steps you’ll be in a small gathering room with tables and chairs. There are doors leading to outside viewing platforms that can maybe hold 6 people each. It was quite odd but wonderful.