"This castle will be a landmark, which will last hundreds of years, " Frandsen says.

FORBES: Castle 4 Sale

Frandsen bought ten isolated acres on the edge of a 60-foot cliff, high in the mountains of northern Idaho.

FORBES: Castle 4 Sale

But as DeClements and Frandsen, a 39-year-old home care entrepreneur, gazed out from here onto beautiful Lake Pend Oreille, an eagle flew by them overhead.

FORBES: Castle 4 Sale

Frandsen's house is called Castle Chalon, after his wife.

FORBES: Castle 4 Sale

Caerphilly-based RMB Security Services Limited's Lifestraw - A high-tech water-filter in a straw, invented and manufactured by Swiss company Vestergaard-Frandsen, which uses allows soldiers to drink clean water from any source while out on operations.

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