Visiting the 27th floor observation deck at City Hall is easily one of the best free things to do in L.A. The observation deck provides a 360 degree view of the entire city, including an up close and personal viewpoint of the ever-growing DTLA skyline. One of the most interesting facts about City Hall is that from 1928 to 1964, it was the tallest building in Los Angeles. Per an order in the city charter, no building taller than 15 stories was allowed to be built. That rule was ultimately overturned in 1958, and new skyscrapers started appearing less than a decade later.