On May 11, 1995, over 170 signatory nations agreed to extend the Nuclear Nonproliferation Treaty (NPT) indefinitely. The NPT is an agreement signed by 189 countries to control the spread of nuclear weapons and nuclear technology based on the principles of disarmament, non-proliferation, and the use of nuclear technology for peaceful purposes. The treaty was opened for signature in 1968 with a provision for review conferences every five years. During the 1995 review conference in New York City, member countries decided to keep the treaty open indefinitely. Learn more about the Nuclear Non-Proliferation Treaty from the United Nations.

On May 11, 1682, the Massachusetts General Court repealed two laws that had banned the celebration of Christmas and had authorized capital punishment for expelled Quakers returning to the colony. Learn more about the state's ban on Christmas.