The Kline Biology Tower, Yale's tallest building, sits at the top of Science Hill. At 14 stories, the tower may be too tall, but Johnson's design is masterful in its aesthetic connection with buildings centuries older on campus. Indeed, the handling of the brick and brownstone of Kline ties it — in color and, to some extent, in shape — to Sturgis's work on the Old Campus and other surrounding structures. Johnson was also responsible for the Kline Geology Building and the extension to the Chemistry Building, weaving these together with earlier buildings to define one of Yale's most masterful courtyards.