In 2005, Barnes' original building underwent a $67 million expansion designed by Swiss architects Jacques Herzog and Pierre de Meuron.[1] The addition was built on a "town square" concept meant to open up Barnes' boxlike building through accessible gathering spaces.[45] Its central element is an abstract geometric tower made of aluminum mesh panels, built for Herzog & de Meuron by the Minnesota firm Spantek,[46] and glass windows that holds the theater, restaurant, and shop spaces.