With the invasion of rock, out-of-control crowds became more commonplace. The 1970 season was a watershed year. At a Steppenwolf concert on July 26, 150 gate-crashers attempted to enter. On July 28, about 100 "hippie-types," according to the Washington Star, crashed the gates for a Procol Harem concert. Fights broke out, the pavilion sustained $1,000 in property damage and five people were arrested. The following night, July 29, The Who and Led Zeppelin sold out the pavilion, but more than 10,000 people without tickets showed up. To avoid a repeat of the previous night's troubles, Merriweather management opened the gates and admitted the huge crowd. There were the usual problems with drugs, but the concert went off without violence according to news reports.