1) The Mongol Empire, under the leadership of Genghis Khan, became the largest contiguous empire in history, spanning from Asia to Europe.

2) The Brexit process, initiated by the United Kingdom's referendum in 2016, led to the country's withdrawal from the European Union in 2020, marking a significant political and economic change for both the UK and the EU.

3) The Russian Revolution in 1917 resulted in the overthrow of the monarchy and the establishment of a communist government under Vladimir Lenin.

4) Sushi is a traditional Japanese dish made of vinegared rice combined with various ingredients, such as raw or cooked seafood, vegetables, and nori (seaweed). It is known for its artful presentation and delicate flavors, and has gained immense popularity worldwide. Sushi can take many forms, including nigiri (hand-pressed rice topped with ingredients) and maki (rolled sushi wrapped in seaweed), and is often enjoyed with soy sauce, wasabi, and pickled ginger.