The Strawberry Fields memorial is dedicated to the memory of John Lennon, and named after one of his songs, "Strawberry Fields Forever." It is located in New York's Central Park just across from the Dakota Building where John got shot and killed in 1980. It was inaugurated by Yoko Ono on John's birthday, 9 October 1985.
The memorial is a triangular piece of land falling away on the two Park sides, whose focal point is a circular pathway mosaic of inlaid stones, made by Italian craftsmen as a gift from the city of Naples. In the center of the mosaic is a single word, the title of one of Lennon's most famous songs: "Imagine". Along the borders of the triangular area surrounding the mosaic are benches which are endowed in memory of other individuals, maintained by the Central Park Conservancy.
You can read more about this place at Wikipedia.
When I visited the memorial in 2006, a homeless man named Chuck told me that he and other friends keep putting fresh flowers or sometimes strawberries on the mosaic. He pays for the flowers out of his own pocket, so give him a dollar if he is still there.