On September 6, 1522, the Victoria dropped anchor at Sanlucar de Barrameda at the mouth of the Guadalquivir, the first ship in history to sail all the way around the world. Eighteen men were aboard, out of roughly 270 who had left the same port almost three years earlier. Juan Sebastian Elcano was in command.
The expedition had sailed in September 1519 with five ships, looking for a western route to the Maluku Islands. Everything went wrong. One ship sank. One was abandoned in the strait that now carries Magellan's name. One turned back. One was captured by the Portuguese. Ferdinand Magellan himself was killed on Mactan in the Philippines in April 1521. Elcano took what was left, the Victoria and a cargo of cloves loaded in Tidore, and decided to keep going west across the Indian Ocean and around the Cape of Good Hope rather than risk the Portuguese patrols.
That decision is why the voyage is called a circumnavigation. Elcano knew the ship might not make it. The crew ate biscuit reduced to weevil-ridden dust and drank water that had gone foul, and men kept dying of scurvy right up to the end. They did not stop anywhere on the long leg home except to take on water and wood, because the whole point was to avoid the Portuguese.
The surviving cargo paid for the trip. The Victoria brought back a hold of cloves, and the sale covered the cost of the entire expedition, losses included. Spain and Portugal went on arguing over who owned the Spice Islands, and settled it in the Treaty of Zaragoza in 1529.
What the crew had actually settled was larger than a trade dispute. A ship had left Europe going west and come back from the east, and the planet's size had been measured by the time it took. Magellan's chronicler Antonio Pigafetta kept the journal that supplies most of what is known about the voyage. Elcano died in 1526, on a second expedition to the same islands.