I like this quiz, but was it necessary to do 5 sites from the USA? There are countries that have more sites, but the most of any other country is 2 sites here...
There are 1200+ heritage sites so doing all of them is not realistic (the dots would completely blot out the map) but i don't see why this can't be pushed to 50, 60, 70, 100 sites. Or at least series, either of a random selection like this quiz or by country/region (like, name 40 sites in south america, or name all sites in Italy)