Two developments were involved. After the first civil rights laws were passed, rebellions by lower class blacks broke out in over 100 cities, with nights of violence against police and looting and burning of local white-owned businesses. The inner neighborhoods of many major cities, such as Detroit and Newark, were burned out. National Guard and Army troops were called out. At one point machine gun units were stationed on the steps of the Capitol building in Washington to prevent rioters from burning it down. Every summer from 1964 through 1970 was a "long hot summer." Whites and Hispanics did not riot.