Chicago VII is the sixth studio album by American rock band Chicago. It was released on March 11, 1974, by Columbia Records. It is notable for being their first double album of new material since 1971's Chicago III and remains their final studio release in that format. It features session percussionist Laudir de Oliveira, who would become a full-fledged band member for the release of Chicago VIII the following year. No. 1 on the Billboard 200 for 1 week, from the issue of April 27, 1974. Wiki link