This crown was once worn by Russian grand duchesses at their weddings. It now sits in the mansion at Hillwood Estate & Gardens in DC.
The crown was purchased in 1966 by Marjorie Merriweather Post, who inherited Post Cereals, worth $20 million. She collected fine art, especially Russian art, and planned to open her house to the public after her death (which she did).
Hillwood makes for an interesting visit, not only because of the many objects on display, but because you get to see how the wealthy lived in the 1950s. The house and the grounds are beautiful.