The Internet is a scary place. Want to know what's even scarier? Shortwave radio. Human history is littered with unexplained, terrifying radio transmissions. In the aftermath of World War II, amateur radio enthusiasts started encountering unidentified transmissions on the airwaves. Broadcast by numbers stationsanonymous, shortwave AM radio stations that transmit messages at pre-set timesmany of these cryptic recordings have been playing for decades. In the mood to NEVER SLEEP AGAIN? Here are 4 terrifying radio transmissions that nobody can explain.

1. "The Swedish Rhapsody" station:

The "Swedish Rhapsody" station is probably the most famous numbers station in the world. Why is it such a big deal? Because it started broadcasting from Poland in the 70s and it features a tiny ghost child reading numbers in German. Nicknamed "Swedish Rhapsody," the transmission starts off with a music box rendition of Hugo Alfvén's 1903 masterpiece. Although the original broadcast went quiet in 1997, copycat stations were picked up as recently as 2007. What happened to it? Nobody knows because Polish ghost children don't like to explain their PR decisions to humans. 

2. "The Lincolnshire Poacher" station:

Looking to make your anonymous radio transmission as disturbing as possible? You should probably nickname it "The Lincolnshire Poacher." Oh wait, never mind, you can't because that already happened in the 70s and your station will never be able to compete with this one. "The Lincolnshire Poacher" earned its moniker from its nightmarish cold opener. Every broadcast would start off with two bars from the 18th-century English folk song of the same name. What happened next? A Daft Punk-esque English female voice would start reading out groups of five numbers. Amateur shortwave enthusiasts purportedly traced the signal to a Royal Air Force base on the island of Cyprus. It has been inactive since 2008. 

3. UVB-76 a.k.a. "The Buzzer" station: 

Commonly known as "The Buzzer," UVB-76 has been transmitting creepy buzzing noises since the disco era. Ready for the "you'll never sleep again" part? Every few years, the buzzing is randomly interrupted by a voice over reading off names and numbers in Russian. The broadcast also features strange banging noise and half-whispered phone conversations. Key takeaway: The 70s was a really great time to broadcast weird messages on shortwave radio.

4. "Yankee Hotel Foxtrot" Station:

Nicknamed the "Yankee Hotel Foxtrot," this numbers station made its terrifying debut in the 60s. Also known as E10, the broadcast was hosted by an otherworldly female Mossad agent who was super passionate about the "Yankee Hotel Foxtrot." When she's wasn't busy foretelling Wilco's domination of the alt-rock scene, the lady spent a lot of time reading the phonetic alphabet. After 50 years, the 24-hour broadcast began to sputter out in 2010. The last known broadcast was recorded on March 1, 2011. We'll leave you off with an interesting piece of music trivia: Wilco had to pay thousands of dollars to the owner of the radio recordingsa small UK record labelafter they illegally sampled the transmissions on their best-selling 2001 album "Yankee Hotel Foxtrot."