What was going on in the world when Marie curie discovered radioactivity?

Answer 1

Marie isolated radium in 1902 and got the Nobel prize in 1903.
During those years the following also occurred:
The second Boer war ended.
The first movie theater opened.
Ray Kroc (owner of McDonald's Hamburgers) was born.
The first Tour de France race took place.
The wright brothers made their first powered flight.
Lawrence Welk was born.