On the opening day of 83-year-old artist Christo’s new exhibition and large-scale installation in London he stands defiantly in front of his new floating artwork, constructed with 7,506 oil barrels in Hyde Park, reminding – no, berating – a crowd of media and fans about the fact that his work is entirely self-funded. He doesn’t take commissions from brands or institutions. “We pay with our money! No grants, no money from the industry,” he proclaims. “All these projects get initiated by us. Nobody asked us to do it. Nobody asked us to wrap the Reichstag. Nobody asked us to install floating piers. We decided that we do exactly what we like to do.” And this, he believes, is what gives him the freedom to create work like “The London Mastaba” and countless other provocative projects, many of which were masterminded while his late wife and creative collaborator, Jeanne Claude, was still alive. The “we” most certainly refers to Jeanne-Claude, because nearly 10 years after her death, few Christo projects are solely the invention of Christo. The “Mastaba” is a form that the two artists have been referring to since the 1960s. It’s a bench-like structure, that they have chosen to supersize, originating from the historical region Mesopotamia. Christo and Jeanne-Claude’s first oil barrel mastaba was completed in 1968. The installation was almost two stories high, filling the whole 50-by-50-foot atrium of the Institute of Contemporary Art in Philadelphia. If Christo has his way again, the 65-feet-tall structure on show in London will soon be dwarfed by an even more ambitious project planned for Abu Dhabi. He wants to build the largest sculpture in the world, once again in the shape of a mastaba. According to the Christo and Jean-Claude website, the structure will be made of 410,000 multi-colored barrels and will stand nearly 500 feet high. The project has been in the making since their first visit to Abu Dhabi in 1979. “It’s a very crucial time. A very crucial time,” he said when asked about progress. “Christo and Jeanne-Claude: Barrels and The Mastaba 1958–2018” is on at the Serpentine Gallery until 9 September.