Just southwest of the Serpentine is a memorial installed in honour of the late Princess Diana. The modern fountain, which resembles a small river rather than a fountain, was inaugurated in 2004 by Queen Elisabeth II.

The memorial was designed by the American landscape architect Kathryn Gustafson, using computer modelling techniques.

The circular fountain consists of 545 pieces of Cornish granite. Water flows from two sides at the top into a small pool at the bottom.