Russia showed up 12 days late to the 1908 Olympics due to using a different calendar

Remember that time you showed up 20 minutes late to a party because you forgot to reset your watch? Well, that is not nearly as bad as what happened to the country of Russia in 1908, who showed up to the Olympic Games an entire 12 days late after using a different calendar than the rest of the world. They were still using the Julian calendar - an older iteration of the calendar - and had not yet switched over to the Gregorian calendar, which was being used by most of the world.