Kennedy launched new strategies to respond to the Cold War threats, including flexible military response, the Alliance for Progress, and Peace Corps volunteers. The Bay of Pigs invasion failed to overthrow Castro in Cuba. During the Cuban Missile Crisis, the U.S. and USSR came close to nuclear war but reached agreements to establish a hotline and remove missiles from Turkey and Cuba. Kennedy and Khrushchev signed a Nuclear Test Ban Treaty and the Berlin Wall was built, symbolizing East-West divisions.