(AP) — The International Space Station marks a big milestone Monday. That’s the 20th anniversary of the first crew’s arrival, and there has been a steady stream of people living there ever since. During those two decades, 241 people from 19 countries have visited the orbiting outpost, including several tourists who paid their own way. The station was a cramped, humid, puny three rooms when an American and two Russians arrived in 2000. Now it’s now almost as long as a football field and has about a dozen rooms. The station’s current residents plan to mark Monday’s milestone by sharing a special dinner.