You may know Columbus, Cortes and Magellan, but those brave men were just a few of the adventurers who crossed the globe by boot and boat when the earth was mostly unmapped. Through history, thousands of explorers have been paid by kings and tempted by the allure of the unknown who pushed into the dark regions of the map. Many have been forgotten by time. Some don’t get the attention they deserve. Know your history. These are explorers you’ve never heard of.

Ernest Doudart de Lagree (1823 – 1868)

The mighty Mekong River still holds mystery today, hosting an unknown number of man-sized catfish and stingrays, the largest freshwater fish on earth. In 1866, however, the river was far more mysterious to the western world, having only been superficially explored by Spanish and Portuguese missionaries. Then, a growing superpower, France aimed to open up the east Asian river, and so the French sent in one of their finest naval officers: Capitaine de Fregate, Ernest Doudard de Lagree. The captain led his expedition as far upriver as boats would go before rapids kept the men from navigating further. Then, the climate and harsh jungle conditions took their toll. Ulcers, fever, dysentery and infected leech wounds wreaked havoc on the crew, and Lagree died from an abscess on his liver. Lucky for him, his heart made it back to France, literally. A doctor removed it from his body and had it sent back to the fatherland.

Gudrid Thorbjarnardottir (??? – 980)

You know Christopher Columbus, the Genoan seafarer generally regarded as the answer to, “who discovered America?” You’ve probably heard of Erik the Red and his son Leif Eriksson too, Nordic adventurers immortalized in folklore to have made Canadian landfall in the late 10th century (that Nordic folklore even describes the people who preceded the vikings, the Native Americans, called Skraelings). You’ve probably never heard of Gudrid, however. The daughter of a slave, Gudrid accompanied Erik the Red to Greenland, married his yougest son Thorstein and then followed Thorstein on a quest to the mysterious western lands called Vinland. Today, we know Vinland as Newfoundland, Canada. And we know Gudrid as the first European to ever give birth on American soil. Her son was named Snorri.

Willem Janszoon (1571 – 1638)

Speaking of Christopher Columbus, Willem Janszoon is basically the Columbus of Australia. A Dutch navigator, he first set foot on Australian soil in 1606 while looking for riches in the haphazardly charted east indies. Of course, like America, someone was already there, with aboriginal Australians first arriving by boat some 40,000 to 60,000 years before Janszoon (and some 30,000 years before the first Americans crossed over the Bering Strait). Janszoon met these original Australians, enlisting the men for hunting meat. The locals eventually grew tired of their guests, and, after a number of his compatriots were killed and some of their boats destroyed by fire, Janszoon escaped Australia and island hopped back home. He retired after more than a decade in politics.

Francisco de Orellana (1511 – 1546)

Maybe the best-known explorer on this short list, Francisco de Orellana was tasked with finding the “Land of Cinammon.” He first departed Quito, in what is now Ecuador, and ventured into the dark heart of South America. Instead of spice, Orellana found danger, with hundreds of his men dying of disease and wounds incurred during battle with the local Cambeba people, whose habitations once dotted the riverbank from the Amazon’s source in the Andes to its mouth in Venezuela. It took him several ships, built under impossible circumstances on the river’s shore, but Orellana survived the whole trip, becoming the first human to ever travel the length of the Amazon. Orellana’s impact is lasting, inspiring Werner Herzog’s strange 1972 classic Aguirre, the Wrath of God, and leaving a trail of unintentional death in his wake. The legacy of smallpox on a population with no resistance to the disease.

Xuanzang (600 – 664)

Whether they circumnavigated the globe by boat or crossed a continent by foot, few explorers in history experienced as many vibrant cultures as those seen by the Chinese scholar and adventurer Xuanzang. For this Buddhist monk, the adventure began with a dream which told him to go west, and so he did. Traveling by foot across the Gobi Desert, through thief-infested territories in remote northern China to modern Kyrgyzstan, Uzbekistan and through the fabled Iron Gates of the Pamir Mountains. At that point, his journey was just beginning, with stops in modern Afghanistan, Pakistan and a winding pilgrimage through India still to come. In all, his journey lasted more than 15 years, and ended just where it began: Ch’ang An, where Xuanzang spent his remaining years writing about western Asia and translating Buddhist texts.