Architecture firm Skidmore, Owings and Merrill (SOM) have unveiled a long-term masterplan to develop a vast new urban district in Philadelphia. The scheme, which is centred around the city’s 30th Street Station precinct, envisions 40 new acres of open space and 18 million square feet of new development, including an entirely new mixed-use neighbourhood. Over the next three decades and beyond, city planners want the station to become a new