These days, with all the theories about the Earth being flat and our planet being constantly visited by aliens or time travelers, it's difficult to take a lot of conspiracies seriously. We tend to think of them as far-fetched fictions made up by basement-dwellers who don't have anything better to do with their time than make up lies on the internet.

And yet, there's sometimes some truth to be found in the stories. Here are 7 conspiracy theories that turned out to be every bit as genuine as the tin-foil-hat-wearers claimed they were...

1. MK Ultra

For years, people thought the government was experimenting with mind control, but it was difficult to prove. Eventually, it transpired that the CIA had been testing the effects of LSD on people, and had conducted more than 150 human experiments between 1953 and 1964. Many of these took place without the subject's consent or knowledge.

2. The FBI spied on Martin Luther King

During his lifetime, many people believed that Martin Luther King Jr. was being spied on. This turned out to be 100 percent true, as the FBI believed that King might have had communist connections and influences. While it ultimately transpired that he wasn't involved in any political subversion, it was discovered that he had been unfaithful to his wife - and that information was eventually used against him.

3. The Gulf of Tonkin Incident 

In August 1964, America became involved in a skirmish that would eventually lead to their participation in the Vietnam war. The USS Maddox claimed to have fired on two North Vietnamese targets - but either one or both incidents are now believed to be false. Whether or not it happened at all is still up for debate, but one thing has been confirmed: the original claims that Vietnam attacked first were definitely false.

4. The US government poisoned alcohol supplies

Back in the 1920s, the production and distribution of liquor was prohibited in America, but it didn't do much to curb people's drinking habits. However, when people started getting seriously sick (or even dying) after consuming bootlegged alcohol, it seemed as if something was being done to deter drinking. And it was. Later on, it transpired that the government had been adding toxins like benzene and mercury to the booze, and had killed around 10,000 people by doing so.

5. Governments are using bots

When we see a dissenting opinion expressed online, it's easy to write it off as a troll or a bot for the sake of preserving our sanity - but it turns out we've been right all along. A recent study of "internet freedom" found that 30 governments in 65 countries are using some kind of online manipulation in order to distort information and swing voters' opinions.

6. The FBI spied on Ernest Hemingway

Later on in his life, author Ernest Hemingway became extremely paranoid that the government was spying on him. However, as his mental health appeared to be in a steep decline, not many people believed him. After his suicide, it was revealed that Hoover himself had placed the writer under surveillance, as he was suspicious of his links to Cuba.

7. Governments hid the truth about tobacco 

Everyone knows today that smoking is terrible for your health. It causes cancer, puts people at risk of a stroke, and can lead to serious breathing problems. Years ago, however, the public wasn't as clued up about the negative effects of tobacco - but the government was. In exchange for generous donations and positive lobbying, politicians covered up the truth about tobacco. In 2006, however, tobacco firms were found to have "suppressed research … destroyed documents … [and] manipulated the use of nicotine so as to increase and perpetuate addiction".

So, next time you go to mock someone who believes in Roswell or area 51, just remember that sometimes the government is hiding information from us.

These days, with all the theories about the Earth being flat and our planet being constantly visited by aliens or time travelers, it's difficult to take a lot of conspiracies seriously. We tend to think of them as far-fetched fictions made up by basement-dwellers who don't have anything better to do with their time than make up lies on the internet.

And yet, there's sometimes some truth to be found in the stories. Here are 7 conspiracy theories that turned out to be every bit as genuine as the tin-foil-hat-wearers claimed they were...

1. MK Ultra

For years, people thought the government was experimenting with mind control, but it was difficult to prove. Eventually, it transpired that the CIA had been testing the effects of LSD on people, and had conducted more than 150 human experiments between 1953 and 1964. Many of these took place without the subject's consent or knowledge.

2. The FBI spied on Martin Luther King

During his lifetime, many people believed that Martin Luther King Jr. was being spied on. This turned out to be 100 percent true, as the FBI believed that King might have had communist connections and influences. While it ultimately transpired that he wasn't involved in any political subversion, it was discovered that he had been unfaithful to his wife - and that information was eventually used against him.

3. The Gulf of Tonkin Incident 

In August 1964, America became involved in a skirmish that would eventually lead to their participation in the Vietnam war. The USS Maddox claimed to have fired on two North Vietnamese targets - but either one or both incidents are now believed to be false. Whether or not it happened at all is still up for debate, but one thing has been confirmed: the original claims that Vietnam attacked first were definitely false.

4. The US government poisoned alcohol supplies

Back in the 1920s, the production and distribution of liquor was prohibited in America, but it didn't do much to curb people's drinking habits. However, when people started getting seriously sick (or even dying) after consuming bootlegged alcohol, it seemed as if something was being done to deter drinking. And it was. Later on, it transpired that the government had been adding toxins like benzene and mercury to the booze, and had killed around 10,000 people by doing so.

5. Governments are using bots

When we see a dissenting opinion expressed online, it's easy to write it off as a troll or a bot for the sake of preserving our sanity - but it turns out we've been right all along. A recent study of "internet freedom" found that 30 governments in 65 countries are using some kind of online manipulation in order to distort information and swing voters' opinions.

6. The FBI spied on Ernest Hemingway

Later on in his life, author Ernest Hemingway became extremely paranoid that the government was spying on him. However, as his mental health appeared to be in a steep decline, not many people believed him. After his suicide, it was revealed that Hoover himself had placed the writer under surveillance, as he was suspicious of his links to Cuba.

7. Governments hid the truth about tobacco 

Everyone knows today that smoking is terrible for your health. It causes cancer, puts people at risk of a stroke, and can lead to serious breathing problems. Years ago, however, the public wasn't as clued up about the negative effects of tobacco - but the government was. In exchange for generous donations and positive lobbying, politicians covered up the truth about tobacco. In 2006, however, tobacco firms were found to have "suppressed research … destroyed documents … [and] manipulated the use of nicotine so as to increase and perpetuate addiction".

So, next time you go to mock someone who believes in Roswell or area 51, just remember that sometimes the government is hiding information from us.