I have seen pictures of Roosevelt, Churchill, Stalin and Chiang, all in places like Tehran, Yalta, Casablanca, and Newfoundland. How did they travel to get there. Like for Churchill and Roosevelt to get to Yalta, they would've needed to go through a war zone, no? As well, how Chiang Kai-shek travel all the way to Tehran?
When Churchill crossed the Atlantic to meet Roosevelt in Newfoundland in August 1941 Churchill travelled on the HMS Price of Wales, an almost new Battleship. The ship was capable of in excess of 25 knots which meant it was a very difficult proposition for submarines to deal with.
His departure from the UK was not publicised before hand which would have added to his security and I think I recall that subsequent to the initial conference he spent some time in Canada and his diary was arranged so that when the day came for his departure from Canada it wasn't readily apparent that was happening.
Just in passing the ability of fast ships to be "submarine proof" was shown many times during World War 2 when the fastest pre-war liners of the day were used as North Atlantic transports outside of the convoy system. They just headed out to sea on their own and put their foot down.
There are [a few answers on a previous post] (http://www.reddit.com/r/AskHistorians/comments/2syu1b/how_did_world_leaders_travel_to_conferences/), though plenty of scope for further details.
By and large, Stalin didn't travel very much, Roosevelt and Churchill travelled by plane and ship; there's a fairly extensive article about Churchill's travels [at the Churchill Centre] (http://www.winstonchurchill.org/publications/finest-hour/finest-hour-148/getting-there-churchills-wartime-journeys). I'm not sure about Chiang Kai-shek, perhaps someone else could chip in.