World, the 20th century was marked by: Two devastating world wars. The Great Depression of the 1930s. The end of vast colonial empires. Rapid advances in science and technology. Moving to moon, mars and beyond. The Cold War between the Western alliance and the Warsaw Pact nations. A sharp rise in living standards in North America, Europe, and Japan. Increased concerns about environmental degradation including deforestation, energy and water shortages, declining biological diversity, and air pollution. The onset of the diseases, aids, epidemic (covid 19). The upcoming superpowers. The planet's population continues to explode 7,684,292,383 in July 2020. For the 21st century, the continued exponential growth in science and technology raises both hopes advances in medicine, agriculture, culture misunderstandings. Superpowers are still developmenting omore lethal weapons of war.