Can you guess whether these events happened in the 19th century or 20th century?

Did it happen in the 19th century or in the 20th century? When you learn history, the first thing you learn about any event is ‘When did it happen?’. Because history is just like a journal maintained to keep the knowledge of our past intact and even the dates of small events hold a great importance. Many people detest learning history just because there are too many dates to remember. But do you think you have a good knowledge of history? Answer these questions if you know when these events happened.