For the past nine years, Jacques Herzog and Pierre de Meuron, who established the architecture firm Herzog & de Meuron in Basel, Switzerland, in 1978, have been working tirelessly  on Tate Modern’s $394-million expansion. The duo, who designed the original Tate Modern, which opened in 2000, were tasked with linking the existing structure to a new, ten-story building. The revamped Tate Modern, which offers sixty percent more exhibition space, will open to the public on June 17.