The State Line Courthouse is the inevitable first stop — the only federal building in the United States that sits simultaneously in two states, with a painted stripe across the pavement for the obligatory two-states-at-once photograph. The Perot Theatre, a restored 1924 movie palace funded by Texarkana-born Ross Perot, hosts touring productions and is worth a look for the ornate Atmospheric Theatre interior. The Ace of Clubs House is a genuinely odd 1885 mansion built in the shape of a playing card club symbol — three circular bays under a dome — now a furnished period museum. The Museum of Regional History covers the Four States area including Scott Joplin's local connections, and the Regional Arts Center occupies a handsome WPA-era building with rotating art exhibitions.