11_diagonal_street | floorarea | 1200 (square metres) <sep> 11 diagonal street is an office tower in johannesburg, south africa it was built in 1983 to a height of 80 metres it is designed to look like a diamond as it reflects different views of the central business district from each angle of the buildingthe building's architect was helmut jahn 
11 diagonal street has a floor area of 1200 square metres. <sep> no information