where did mark twain travel?

Throughout the Mid and South West in the US, Europe (mainly England, France, Spain and Italy) and the Middle East. He wrote two volumes on these travels. The journeys through Arab and Muslim countries is specially relevant today.

Samuel Clemens did the actual traveling. Mark Twain did the writing.

All over the place. As a young man he went out to the wild west (in the days when it really was wild) and also went to Hawaii. You can read about his travels in 'Roughing It'. He went on a cruise around the Mediterranean, which he wrote about in 'Innocents Abroad'. He travelled in Germany, and wrote about it in 'A Tramp Abroad'.