Rainier III was the Prince of Monaco from 1949 until his death in 2005. He was born on May 31, 1923, and was the son of Prince Louis II and Princess Alice. During his reign, he focused on modernizing the principality and promoting tourism, which significantly boosted Monaco's economy. Prince Rainier III is also known for marrying Grace Kelly, a famous American actress, in 1956. Their union brought international attention to Monaco, and they had three children: Caroline, Albert II, and Stephanie. Rainier III's legacy includes his contributions to the arts and the establishment of the Monaco Grand Prix.