Everyone has to apply for a 24 hour visa upon flight arrivival, including Americans, where approval takes anywhere from 1 hour to 72 hours. If you are approved then, in immigration, you get finerprinted, photoed, questioned, and go through customs/security. If you are not approved within a 1 hour time frame you then will not be approved and thus stay the night at the airport in what I call packed homeless shelters. Luckily my wife and I had an Air Canada rep, who was Korean, and had the process down pat. Still he had difficulty with the "covoluted" process and we were both approved with only a minute left on our 1 hour timeframe. I saw mobs of passengers who didn't have a clue and probably spent the night in that airport.