On June 4, 1989, people in Poland elected their national legislature. An independent, democratic Poland, coming from the history they were coming from, was an astonishing accomplishment and Poles are right to honor the date.
China, on the same day, called out the army and blew the day right out of their calendar. Twenty-five years later, the regime still gets nervous every year and locks up people who might talk about it. The irony is that people today who might not otherwise care much about the events of their parents' generation do notice the bizarre Internet antics required to keep them from Googling this date.
This is the kind of thing that Sims might have a hard time understanding. Because Sunset Valley is not in China, I have taken the liberty of making a Comic.