Vince Ungvary examines a city map of Beijing from a century ago. Mike Peters / China Daily

As a dapper, silver-haired man rolls out one old map, then another, even untrained observers can see that some details are missing. And not small details. Where, for example, is the Pacific Ocean?

"It's hard for us to imagine now that maps made well after Magellan and others circumnavigated the world could look like this," Vince Ungvary says, chuckling. "But that's part of the story of antique maps: Who drew them, and why, is key to what you see."

For example, he says, cartography by Claudius Ptolemy (AD 90-168) showed that the Indian Ocean was landlocked more like a large lake. Because his records were the wisdom of the day well into the Renaissance, "the myth of the 'Indian lake' lived on long after maritime discoveries had refuted it," he says. "And Ptolemy didn't know anything about the Pacific Ocean."

Ungvary got interested in ancient maps by chance.

"I was visiting an old bookstore in New Delhi some years ago. After a good look around, I got curious about a pile of big yellow pages heaped on a table in the back."

"The clerk said, 'Oh, they're just old maps'."

Ungvary was transfixed by the pile and began leafing through it.

"I'd never seen a really old map before, except maybe reprinted in a textbook," he says. "As soon as I saw the odd geography and shapes, I was totally taken with them. The intricate images were oddly intimate - hand-drawn with a lot of details and decoration."

He bought a few, and was soon doing research about his new hobby.