The Rhine River, one of Europe’s ... Over the years it morphed into a sprawling castle estate that is today home to one of the oldest wineries in Germany. The 80 hectares vineyard produces ...

German entrepreneur Jan Henric Buettner was head of AOL Germany in the 1990s and a California venture capitalist in the early 2000s. In 2005, he decided to add castle owner to his résumé.