 Efforts to preserve the city's historic past were evident as long ago as 1934, when the Museum of Science and Industry opened, as did the John G Joicey Museum in the same year.Council housing began to replace inner-city slums in the 1920s, and the process continued into the 1970s, along with substantial private house building and acquisitions.Unemployment hit record heights in Newcastle during the Great Depression of the 1930s.