in Los Alamos, New Mexico, in a test code-named Trinity, and the second, nicknamed "Little Boy", was dropped on Imperial Japan at the end of World War II. After the war, the Oak Ridge National Laboratory became an institution for scientific and technological research. Mid-20th century to present After the U.S. Supreme Court ruled racial segregation in public schools unconstitutional in Brown v. Board of Education in 1954, Oak Ridge High School in 1955 became the first school in Tennessee to be integrated. The next year, nearby Clinton High School was integrated, and Tennessee National Guard troops were sent in after pro-segregationists threatened violence. Between February and May 1960, a series of sit-ins at segregated lunch counters in Nashville organized by the Nashville Student Movement resulted in the desegregation of facilities in the city. On April 4, 1968, James Earl Ray assassinated civil rights leader Martin Luther King Jr. in Memphis. King had traveled there to support striking African American sanitation workers. The 1962 U.S. Supreme Court case Baker v. Carr arose out of a challenge to the longstanding rural bias of apportionment of seats in the Tennessee legislature and established the principle of "one man, one vote". The construction of Interstate 40 through Memphis became a national talking point on the issue of eminent domain and grassroots lobbying when the Tennessee Department of Transportation (TDOT) attempted to construct the highway through the city's Overton Park. A local activist group spent many years contesting the project, and in 1971, the U.S. Supreme Court sided with the group and established the framework for judicial review of government agencies in the landmark case of Citizens to Preserve Overton Park v. Volpe. TVA's construction of the Tellico Dam in Loudon County became the subject of national controversy in the 1970s when the endangered snail darter fish was reported to be affected by the project. After lawsuits by environmental groups, the debate was decided by the U.S. Supreme Court case Tennessee Valley Authority v. Hill in 1978, leading to amendments of the Endangered Species Act. The 1982 World's Fair was held in Knoxville. Also known as the Knoxville International Energy Exposition, the fair's theme was "Energy Turns the World". The exposition was one of the most successful, and the most recent world's fair to be held in the U.S. In 1986, Tennessee held a yearlong celebration of the state's heritage and culture called "Homecoming