Rising 20 metres above the surface of Serpentine Lake in London's Hyde Park is a giant stack of colourful oil barrels in the shape of an ancient Egyptian tomb.
It's the brainchild of Bulgarian artist Christo, who's fascinated by the shape of the mastaba - a pre-pyramids Egyptian tomb that's a rectangle with sloping sides and a flat roof.
Christo's creation is made from 7,506 55-gallon drums assembled around a structure of scaffolding, which is floating on a platform of plastic cubes, held in place by 32 six-tonne anchors.
Dubbed 'The London Mastaba', it's painted red and white on the slanting walls, while the flat ends of the barrels are painted an assortment of blue, mauve, and a lighter red.
"The colours will transform with the changes in the light and its reflection on the Serpentine Lake will be like an abstract painting," says Christo.
The hollow art installation takes up 1 percent of the lake's surface area, and weighs a whopping 600 tonnes.
The project was devised and funded entirely by Christo, who refuses commissioned jobs and doesn't accept payment for his public works.
It's his first sculpture in the United Kingdom - which will float on the lake until September 23.
Christo's now setting his sights on creating another mastaba structure, which will be much bigger, and set in the middle of the desert in United Arab Emirates.
He came up with the idea with his late wife Jeanne-Claude in 1977, and while construction is still some time away, it will be their only permanent sculpture in the world.
It will be taller than the Great Pyramid of Giza by around four metres, standing 150m from the desert floor. It's footprint will be 60m wider as well.