April 22 (UPI) -- On this date in history: In 1500, explorer Pedro Álvares Cabral arrived in South America, claiming what would later be known as Brazil for Portugal. In 1889, about 20,000 homesteaders massed along the border of the Oklahoma Territory, awaiting the signal to start the Oklahoma land rush. In 1914, U.S. forces took control of the Mexican port city of Veracruz during the fighting of the Mexican Revolution. In 1915, during World War I, German forces became the first to use poison