PHS Philadelphia Flower Show - billed as the world's largest indoor flower show

The Pennsylvania Horticultural Society's Philadelphia Flower Show is described by its organizers as the world's largest and longest-running indoor flower show. The event has been held annually (with occasional interruptions) since the 19th century and in recent years takes place at the Pennsylvania Convention Center. The show features large-scale themed horticultural exhibits and draws hundreds of thousands of visitors and exhibitors from around the world.