In the 19th century, the United States got land from France, Spain, the United Kingdom, Mexico, and Russia, and took over the Republic of Texas and the Republic of Hawaii. Arguments between the farming-based South and industrial North over the growth of the institution of slavery and states' rights began the American Civil War of the 1860s. The North's victory prevented a permanent split of the country and led to the end of legal slavery in the United States. By the 1870s, the national wealth was the world's largest. The Spanish–American War and World War I confirmed the country's status as a military power. In 1945, the United States came out from World War II as the first country with nuclear weapons, a permanent member of the United Nations Security Council, and a founding member of NATO. The end of the Cold War and the breaking up of the Soviet Union left the United States as the only superpower. The United States participated in the Space Race that produced rapid advances in rocketry, materials science with the National Aeronautics and Space Administration. Apollo 11 was the first flight to send people to the moon. It was done by NASA, the American space group. It went up to space on July 16, 1969, carrying three astronauts: Neil Armstrong, Buzz Aldrin and Michael Collins. On July 20, 1969, Armstrong and Aldrin became the first humans to land on the moon, while Collins stayed in orbit around the Moon.