An artwork/sculpture made of concrete in the north east corner of Bernie Spain Gardens, next to the Oxo Tower, South Bank, London.
The artwork is designed for a person to recline on so that they can see St Paul's Cathedral on the other side of the river.
https://londonist.com/london/secret/what-s-this-sloped-stone-pedestal-thing-near-the-oxo-tower
Possibly by Karen Richmond?
177 photos taken in November 2020 with a Sony a6000 and processed in Reality Capture.