The entrance was found by accident. Nobody saw it. On October 21 the ships reached a headland at about 52 degrees south, which Magellan named Cape Virgenes, and a storm caught them as they explored the bay beyond it. Two of the vessels, the Concepcion and the San Antonio, were driven through a narrow opening that could not be seen from open water and came back to report it. The fleet went in after them, checking the water as they went, and unlike the river mouths they had tried before, this one stayed salty and the soundings stayed deep.
It is cold there. The passage was roughly 350 miles long, narrow, cold and lined with channels that led nowhere. Smoke on the southern shore told them the land was inhabited, and they saw fires at night, which is where the name Tierra del Fuego comes from. Magellan sent two ships to explore the branches and told them to come back within days. The San Antonio did not come back. Its pilot, Estevao Gomes, had argued for turning home, overpowered the captain, and took the ship back across the Atlantic to Spain, where the crew was put on trial.
The three ships that were left reached the far end of the strait on November 28, and the water beyond it was so calm after the channel that they called it the Pacific. The crossing of that ocean took more than three months, far longer than Magellan had planned, and the men ate sawdust and rats before reaching Guam and then the Philippines, where Magellan was killed in a fight on Mactan in April 1521.
One ship came home. The Victoria, under Juan Sebastian Elcano, reached Spain in September 1522 with eighteen men out of the two hundred and fifty who had sailed, and the cargo of cloves it carried paid for the entire expedition. The strait itself was used for four hundred years as the route between the oceans, until the Panama Canal opened in 1914 and took most of the traffic away.