"It's the only explanation anyone can seem to agree on," Matthias says, his tone apologetic if only because he remembers well how he had wondered the same things, and how difficult it had been to accept them. Only time and seeing it with his own eyes had made it true.

"It's like some kind of invisible barrier. You can walk, take a ship, even an automobile. But if you go too far you get turned around. It's maddening," he admits.