AstroBarry has written a great article on the subject.
Whenever Uranus and Pluto come together in any hard aspect (i.e., conjunction, opposition or square), we witness a period of increased societal unrest and turbulence, during which issues of human rights and social welfare are more loudly addressed. Astrologer-academic Richard Tarnas does a great job of detailing the historical specifics of what he calls these 'epochs of revolution' associated with Uranus-Pluto contacts. The last two of these revolutionary Uranus-Pluto periods in our recent history were (1) the mid-1960s, a time so renowned for these qualities that 'The Sixties' has essentially become a brand-name for describing progressive social change, and (2) the Great Depression during the first half of the 1930s, which followed the massive financial crash of 1929 and led to debates about the consequences of free markets, government interventions, and unequal distributions of wealth which uncannily mirror the content of today's public discourse.
Read his full Pluto Square Uranus article here. A great and informative read.