5. Michael Douglas & Catherine Zeta-Jones - 2000
Estimated Cost: $1.5 million
Can you imagine wearing a $300,000 diamond tiara on your wedding day? Well, that's what Catherine Zeta-Jones sported when she married Michael Douglas. She also wore a Christian Lacroix gown that cost $140,000. They tied the knot at the famed NYC Plaza Hotel, where wedding packages start at $375 per person.