Journey to the Centre of the Earth · Jules Verne, 1864
How far did they travel in Journey to the Centre of the Earth?
3,829km
From Snæfells in Iceland to Stromboli off Sicily is 3,829 km in a straight line. They went in through one volcano and came out of another.
From the bookThe map's guessReal world
The 3,829 km is the great-circle distance between the two volcanoes. It happens to pass under Scotland and England.
Their actual path is longer and mostly unknown. Port Gräuben, where they build the raft, is about 350 leagues (1,400 km) from Iceland by Lidenbrock's figures, rounded. Verne doesn't map the way up to Stromboli at all, so that part of the route is a guess.
On this map depths are stretched 8× so you can see them. At true scale the whole journey would be a thin scratch under the surface.
See where they came out