Lord Voldemort is one of the greatest villains of all time. That's not even up for debate. The man's closest ally is a snake. He fractured his soul into seven Horcruxes and hid them all around the world. He spent a year hiding in the back of a turban, breathing the very same air as his nemesis, all the while evading detection. He has no nose, for God's sake!
Long story short, this man is as badass as he is evil.
But one thing J.K. Rowling's books never really explained was: What happened between Tom Riddle going into hiding and re-emerging as He Who Must Not Be Named to get all Avada Kedavra on the asses of every good wizard and witch in the land?
This is clearly a question that has been playing on the mind of Reddit user Obversa, who recently posted a very detailed theory outlining what happened after Riddle's disappearance. You can read the full theory here, but as a human being with limited time, you might want the condensed version, which is as follows:
Tom Riddle visited Castelobruxo, the Brazilian school of magic, where he collected the venom of a viper and used it to create his own snake Nagini, into which he transferred one of the fragments of his soul.
There's some compelling evidence for this theory, such as the fact that the effects of the curse on the wearer of Marvolo Gaunt's ring are strikingly similar to the effects of a venomous snake bite.
Benedita Dourado, the headmistress of Castelobruxo, once visited Hogwarts during the Armando Dippet era, and thus it's possible that Tom established some sort of relationship with the school while studying at Hogwarts. On top of that, Castelobruxo students are renowned for their skills in the realm of herbology, and alumni have included potioneer Libatius Borage, who wrote Asiatic Anti-Venoms, among other works.
There are also a ton of weaknesses to this theory, not least of all: Why did Voldemort never hide one of his Horcruxes in Brazil if this was a place he'd spent any serious amount of time? And why would his presence there not have been noted during the long period of time he spent under the radar before resurfacing to assemble his Death Eaters?
Still, until J.K. Rowling descends from her throne to feed us yet another nugget of info, this is just about all we have, so I choose to believe that Tom Riddle did indeed travel in Brazil. We've all dreamed of doing that.