A numbers station is a type of shortwave radio station characterized by unusual broadcasts, often created by artificially generated voices reciting streams of numbers, words, letters, tunes or Morse code. They are transmitted in a wide variety of languages and the voices are usually female, although sometimes men’s or children’s voices are used.
In the 1960s, Time magazine reported that the numbers stations first appeared shortly after World War II and were imitating a format that had been used to send weather data during that war. It is widely assumed that these broadcasts transmit covert messages to spies. This has not been officially acknowledged by any government that may operate a numbers station, and, with a few exceptions, no QSL responses have been received from numbers stations by shortwave listeners who sent reception reports to said stations, which is the expected behavior of a non-clandestine station.
Welcome to Derinkuyu, an underground city that once housed up to 20,000 people. In the Cappadocia region, famous for its cave dwellings and underground villages, Derinkuyu stands out for sheer size and complexity. Locals began digging in the 500s BCE. The city consists of over 600 doors, each of which can be closed from the inside. Each floor could be closed off as well. And just to make attacking completely impossible, the entire city was deliberately built without any logic. Its maze-like layout makes navigating the city nightmarish for unfamiliar invaders.