Prior to 2013, it was commonly cited as having happened about 65 million years ago, but Renne and colleagues (2013) gave an updated value of 66 million years.

Prior to 2013, it was commonly cited as having happened about 65 million years ago, but Renne and colleagues (2013) gave an updated value of 66 million years. -- https://en.wikipedia.org/wiki/Alvarez_hypothesis My first thought reading this is, here they are casually adjusting the date by 1,000,000 years, and meanwhile homo sapiens is 200,000-300,000 years old. Helps illustrates the timescales a little.