The New York real-estate developer Aby Rosen is a man with big buildings, big ambition and the art to match. The highly successful developer and collector is well-known for buying major architectural icons in the city – such as the Seagram Building, the Gramercy Park Hotel and the Lever House – and then restoring them to their former glory; a move that endears him to most but not all. In a recent real-estate controversy, Rosen tried to push through a Norman Foster-designed skyscraper on the sedate Upper East Side, with plans to includes a Kunsthallelike exhibition space. When it was blocked by a local committee, Rosen – to paraphrase The New York Times – dusted off his starry Rolodex and brought a number of art and social celebrities to testify to the project’s merit. Born in Frankfurt and married to the New York socialite Samantha Boardman, Rosen is rather less than publicity-shy, and like many men with starry rolodexes, he sees his artistic counterpart in showmen like Jeff Koons, Andy Warhol and Damien Hirst – all artists represented in his collection, as are other top-tier artists such as Louise Bourgeois, Christopher Wool and Sol LeWitt. While New York contents itself with his gallery on the ground floor of the Lever House, his promised, thwarted Kunsthalle space is probably still somewhere on the cards.