Snopes.com is an excellent skeptical resource and a great place to go to check viral posts or fake news. In the early days of the internet, many urban legends where shared by email and in chatrooms, and because many people had not come across these before, they were inclined to believe them. To counter this, in 1994, Barbara and David Mikkelson created the Urban Legends Reference Pages website to list and detail these stories. The name 'Snopes' originally came from a novel by William Faulkner and had been used by David as a username online.
Following an acrimonious divorce, Barbara sold her share of the business to Proper Media and there but there are ongoing disputes between David Mikkelson and the company. He managed to raise $1/2m through crowdfunding in 2017 and is entirely self-funded (though there have been unfounded accusations by some right-wing conspiracy theorists that it is funded by George Soros). In 2017, they agreed to work with Facebook in fact-checking, though they announced in 2019 they were suspending their partnership - despite the loss of income from FB - to review whether it was successful for them.
Snopes should be your first port of call when confronted with any news shared on social media that is unconfirmed by other independent sources. The site is quoted by many mainstream media outlets as a reputable source and has been praised for its accuracy and even-handedness by other fact-checking organisations.