Today is a day to catch up our current Gregorian calendar to the actual solar year with a extra day in this leap year. Unless the earth is shoved into a different orbit, a complete orbit of the earth around the sun takes exactly 365.2422 days to complete, so the Gregorian calendar using 365 days gets out of whack without adding an extra day every four years. But every four years is too much so the extra rule of any centennial year that is divisible by 400 does have a leap day. But even all the extra tweaking, the leap year rules still adds an extra half minute a year so in 3,000 years or so, people decide what to do.
This old building has seen plenty of leap years and time has not leaped over it but instead the building has endured the harsh weather of the years and it may not see a great number of leap years in its future.
Time Leaping Ahead