The Columbia River, the mightiest river flowing into the Pacific Ocean from the American continents, ends its journey here. Native people have lived along its banks and fished its waters for thousands of years. Euro-American exploration of the river began in 1775, when the Spanish explorer Bruno de Heceta sailed within sight of its mouth, but treacherous waves breaking over the river bar prevented him from entering, though he placed the river mouth on Spanish charts. On May 11, 1792, Robert Gray brought the first ship over the bar and into the river, traded with the Chinooks for sea otter and beaver pelts in exchange for items valuable in their wide trading network, and named the river after his ship, the Columbia. Later that fall, British naval lieutenant William Broughton traveled and charted 100 miles upriver, and his commander, Captain George Vancouver, used "Columbia River" on charts he published in 1798. Seven years later, those charts helped Lewis and Clark confirm their exact location when they reached the mouth of the Columbia.