My son hadn’t even been born when I started secretly writing him a birthday letter each year. As he neared adulthood, I ...

A coded passage in “Kryptos,” Jim Sanborn’s sculpture at CIA headquarters, has gone unsolved for decades. After he announced its auction, two researchers stumbled on the answer.

Every modern automobile carries a 17-character vehicle identification number, an alphanumeric string unique to that single ...

A single leaked hint exposed the CIA’s most puzzling code. But dozens of the world’s toughest ciphers are still waiting to be ...

For years, the mysterious signs found on the city’s murals were thought to be nothing more than decorative symbols. But now, ...

Image: Canon As with other brands, Canon's lenses feature many letters and acronyms in the lens names. Seeing something like ...

Humans have been dancing with divination since time immemorial, but the oldest surviving set of tarot cards, known as the ...

It is clear that the sprawling city of Teotihuacan near Mexico City was a major metropolis of the ancient world, but what do ...