Wakanda’s wealth comes from its vibranium.
In the opening scene of “Black Panther,” Prince N’Jobu (Sterling K. Brown), T’Chaka’s brother, explains Wakanda’s history to his son, Eric Killmonger (Seth Carr). He said that a meteorite containing vibranium, the strongest metal in the Marvel Cinematic Universe, crashed into Africa millions of years ago.
Eventually, five tribes settled on the land where the meteorite hit and called it Wakanda. Later in the film, we learn vibranium is used in all Wakandan technology and tools, making their city superior to the rest of the world.
Wakanda is believed to be the only nation where vibranium exists. For that reason, people, like Ulysses Klaue (Andy Serkis), have tried their hand at stealing the precious metal.
The main source of vibranium comes from Mount Bashenga.