SYDNEY (REUTERS).- American photographer Spencer Tunick is searching for thousands of Australians to strip off on the steps of the Sydney Opera House in the name of art. Tunick, famous for capturing hundreds and sometimes thousands of naked people against industrial or urban backdrops, wants to create a Sydney “installation,” involving up to 2,000 nude volunteers on March 1. The photo, to be called The Base, will coincide with the city’s annual gay and lesbian Mardi Gras, which attracts participants and audiences from around the world. “In a way, I’m making a base for the structure, a base for the architecture, and by combining straight and gay and lesbian people I’m weaving the different sexes and society together to form this wonderful fabric that holds up this gorgeous building,” Tunick told Australian radio on Thursday.