↬ Gregorian Magic
You see, the way Gregorian Calendar works is that each year is 365 days - 52 weeks plus one day. Over time, that one extra day adds up, so we get a pattern where every few years, the days and dates match up. It’s usually in a repeating pattern of ever 6, then 11, then 11 again, and a repeating pattern of every 28 years for leap years - so 2015 shares the same dates with 2009, 1998, 1987, 1981, 1970, and so on.
As it turns out, the entire world knowledge has already beed written, so we can safely look back at 1981.
And thanks to Marvel we can look at a very nice 1981.