Today is the anniversary of the death in 1936 of the last known thylacine, also known as the Tasmanian Tiger, killed by neglect in captivity.
Here's video from 1933:
There's a recent article here that looks at some of what led to the extinction. There is a Thylacine Museum, "an online educational guide to the thylacine or Tasmanian Tiger. Here you will find information on virtually all aspects of the natural history of this unique Australian marsupial." There's a free e-book from a site that holds there's hope some may still survive.