 Complete the following phrase:  The Tijuana Pop Festival was held in the Bullring on 13 October 1968. The festival was slated to feature the Animals, Iron Butterfly, Patchwork Security Blanket, the Collectors, the Chicago Transit Authority and the Yellow Payges; however, the Animals and Iron Butterfly never played. Other issues which marred the event included rumors that the festival had been canceled, long pauses between acts, police activity at the border and at the ring and the political impact of the 