1) The invention of the transistor by Bell Laboratories in 1947 revolutionized electronics and paved the way for the development of smaller, more efficient electronic devices.

2) The Black Lives Matter movement gained renewed momentum in 2020 following the killings of George Floyd, Breonna Taylor, and others, sparking protests and discussions on systemic racism, police reform, and social justice around the world.

3) The Southern Ocean surrounds Antarctica and is the coldest and least-visited ocean.

4) The Cuban Missile Crisis in 1962 brought the United States and the Soviet Union to the brink of nuclear war during the Cold War.