Short answers, pulled from the story.
The first true wave of decolonization began in 1775 within the Thirteen North American colonies. This rebellion against the British Empire established a precedent that independence was possible and inspired movements across the globe.
The Haitian Revolution began in 1789 and escalated into a slave uprising in 1791. Haiti secured its independence from France in 1804, becoming the Empire of Haiti before evolving into a republic.
The British Empire began to dissolve after World War II as the cost of maintaining control became unsustainable. The process involved pragmatic budget demands, constitutional conferences in London, and the issuance of Orders of Council fixing exact dates of independence.
Patrice Lumumba was the first Prime Minister of the Democratic Republic of the Congo. He was executed by the separatist Katangan authorities of Moïse Tshombe after being handed over by Joseph-Désiré Mobutu on the 17th of January 1961.
As of 2020, 17 territories remain under the United Nations classification of non-self-governing territories. These include Anguilla, Bermuda, British Virgin Islands, Cayman Islands, Falkland Islands, Montserrat, Saint Helena, Turks and Caicos Islands, Gibraltar, Pitcairn, American Samoa, United States Virgin Islands, Guam, Tokelau, Western Sahara, New Caledonia, and French Polynesia.
In February 2019, the International Court of Justice in The Hague ruled that the United Kingdom must transfer the Chagos Archipelago to Mauritius. On the 22nd of May 2019, the United Nations General Assembly adopted a resolution affirming that the Chagos Archipelago forms an integral part of the territory of Mauritius.