Image courtesy The Scarlet Hotel.

5. The Scarlet Hotel, Cornwall, England

The property: For adults-only, this luxurious but laid-back property is set on-top a hill making for gorgeous sand and sea views.

Eco-friendly highlights: Features like their “green” roof, energy-efficient lighting, rain water harvesting and locally-made toiletries are just the beginning. Their luxurious spa is one of the greenest in the country, with two chlorine-free pools, including the indoor pool which is headed by solar thermal panels.