Disneyland opened in 1955. Just two years later, this film was shot. This footage has been in the vault, so to speak, since then; it was released by Todd J. Pierce in 2012 after being digitally transferred and cleaned up. The footage isn't miraculous by any means; it's basically very nicely shot film of what Disneyland looked like at the time -- families going about their business, kids on rides, parades, that sort of thing. You see lots of classic rides (the teacups make me dizzy!) and lots of people wearing hats. Have a look, and see if you can spot what has (and hasn't) changed.
For more information, consult Pierce's commentary, which includes the note:
This film was shot the month Monsanto opened the House of the Future. Look, there's no line for the House, with only a few people wandering out its exit.
Having never been to Disneyland in the 1950s or 1960s, I'm not personally familiar with Monsanto's House of the Future. But it sounds kind of intense and was apparently built out of...wait for it...polyester.