Don't know if anyone has these yet or not, but:
517) The more people eat, the more they have sex. Eating huge diets does not result in obesity, but mass orgies. However, this has no effect on the local culture or the level of happiness (whose lack thereof can increase as the population does).
518) As soon as the Eiffel Tower was built, engineers all across the nation hastily built their own radio towers. Even though none of them were nearly as impressive as the Eiffel, many of them had even more effect on the local culture than the Eiffel did. However, nobody in surrounding countries even got started on their towers until later, sometimes many decades later, if ever.
519) Your citizens will get royally pissed off if you go to war with the nation that has Zeus' Statue. They are seriously worried that Zeus will punish their violence by striking them down with lightning bolts.
520) People of multiple religions within one city will always get along, even if one of the religions is declared the state religion.
521) Soldiers can become better trained by staring at a statue of a war chariot.
522) The effects of Stonehenge are living proof that aliens exist, and that they arrived on Earth thousands of years ago: they gave a nation several of its monuments.
523) Banks always have a 50% return rate on investments. However, if this offer is combined with any other investment, the 50% is calculated from the starting, not current, investment.
524) If the local theatre burns down, and volunteers agree to rebuild it, they will do so almost instantly.
525) A field worker, a horse, and a tank can all move at the same speed.
526) The Pyramids really do hold all the secrets...well, at least all the different theories of government.
527) Contrary to popular opinion, bureaucracy increases, not decreases, efficiency.
528) Notre Dame makes every one on the continent a little happier, even if they have never heard of Notre Dame.
529) Societies that are inherently spiritual can deal with major changes in their civilization a lot more easily than those who aren't.