American actress Grace Kelly headed to the Cannes Film Festival in April of 1955 as the head of the U.S. delegation. While she was there, she was a part of a photo shoot where she met Prince Rainier III the prince of Monaco. Later that year, it became public that if the Prince did not produce an heir, Monaco would revert to France. The Prince visited American where he met Grace Kelly with her family. Only three days later, they were engaged. The world waited patiently as the wedding “of the century” was planned. They had both a civil ceremony and a religious ceremony with the civil ceremony being broadcast all over Europe. The religious ceremony was the day after. The newly married couple celebrated with a whopping 600 guests among whom were some of the most high profile celebrities and European heads of state. The bride’s dress was designed by Helen Rose. To this day, Grace Kelly’s dress is one of the most sought after styles–it truly has withstood the test of time. This ceremony was watched by an estimated 30 million people! A little fun fact: Frank Sinatra initially accepted his invitation to attend but last minute decided not to because he didn’t want to upstage the bride.