Arch Allies is a live album recorded by REO Speedwagon and Styx at Riverport Amphitheatre (now Verizon Wireless Amphitheater) in Maryland Heights, Missouri, a suburb of St. Louis. Each band also released single live albums containing only their own tracks from this album. The Styx songs were released alone as At the River's Edge: Live in St. Louis and the REO songs were released as Live Plus, Live Plus 3 and Extended Versions.

Members of the classic rock band THE ORCHESTRA, comprised of former members of ELECTRIC LIGHT ORCHESTRA and ELO Part II, recount the history of the band and how the album of original songs No Rewind came to be.