This Saturday, June 17, a boat is scheduled to arrive in Honolulu. But this is not just any boat: It is a 62-foot-long canoe that has spent the past three years circumnavigating the globe.

The canoe, based on an ancient design, set off from Hilo, on Hawaii’s Big Island, in May 2014 with a crew of 17. It eventually visited 19 countries and traveled more than 46,000 miles, according to Scientific American. The trip was organized by the Polynesian Voyaging Society, and is as much about bringing attention to the effects of climate change as it is about showing how indigenous peoples traversed the Pacific Ocean to settle remote islands hundreds of years before modern navigation.

“For centuries, Europeans stubbornly refused to acknowledge Polynesian achievements because they simply could not believe that a so-called primitive society was demonstrably better at navigation than they were,” Wade Davis, an Explorer-in-Residence at the National Geographic Society, told Scientific American.

The canoe’s navigators use a system known as wayfinding, which has been passed down for generations and requires navigators to commit the paths of hundreds of stars to memory, while also relying on “the direction of waves and the movement of seabirds,” according to Scientific American. The canoe is named the Hōkūleʻa, the Hawaiian name of the Polynesian zenith star (Hōkūleʻa can also mean “Star of Joy”).

The crew of the Hōkūleʻa has been documenting their voyage on Facebook and the Voyaging Society’s website, including visits to Pacific islands that are most susceptible to climate change. Some of those places are less vulnerable to being inundated by rising seas than they are to running out of freshwater as salt water seeps into island aquifers.

“The irony is that the Pacific islands have nothing to do with creating climate change but they are the ones who are suffering the most,” said Nainoa Thompson, president of the Polynesian Voyaging Society. “The good news is that we found thousands of people there full of aloha, full of compassion and caring for the Earth and for the oceans, which give us our life.”