Scientists were beginning to make important discoveries in medicine. Mount Everest had not yet been conquered. No one had yet reached the North and South Poles. Travelling to the moon was only the stuff of science fiction. Techology and the explosion of human knowledge has resulted in remarkable progress in the 20th century.
Communication is instantaneous and global.
The jet has turned our world into a village. But the 20th century also saw the continued weaknesses of humankind. There were two world wars and countless smaller ones. Two-thirds of the world still exists in poverty and hunger. Slavery is still alive in pockets around the world.