The International System of Units (SI): The base units are redefined, making the international prototype of the kilogram obsolete.
The government of Singapore authorised the controversial execution of convicted murderer Kho Jabing for the murder of a Chinese construction worker despite the international pleas for clemency, notably from Amnesty International and the United Nations.
An EF5 tornado strikes the Oklahoma City suburb of Moore, killing 24 people and injuring 377 others.
At least 27 people are killed and 50 others injured when a 6.0-magnitude earthquake strikes northern Italy.
Mamata Banerjee is sworn in as the Chief Minister of West Bengal, the first woman to hold this post.