We've explored five or six international capital cities. Domestically, if you include DC, I'd add another 20-25 to that mix. There are a few that we just didn't have time to stop and it was more of a drive through situation. I know we've driven through Topeka, KS, Harrisburg, PA, Bismarck, ND, Santa Fe, NM and Little Rock, AR with no exploration. I think some also hinges on which capitals are more "destination" cities as well as time on your hands. For example, there is a TON to do in and around Denver, but if you have some downtime and have never been to Wyoming, I know people will make the fairly easy drive up to Cheyenne, since the capital isn't too far past the border. It's also extremely quiet and small compared to most capitals, so it's fairly easy to get around.