Panda twins born last year at Schoenbrunn Zoo in Vienna celebrated their first birthday on Monday with a big party. With plenty of their favorite foods on hand, the pandas received treats from their guests, including visitors and media personnel. The birth of Fu Ban and Fu Feng last August pushed the number of giant panda cubs naturally bred in Vienna to a record five. Of the naturally-bred cubs, three were returned to China when they were old enough to leave their mother.