TripAdvisor’s GreenLeaders Program has seen phenomenal growth since its introduction several years ago. It highlights eco-friendly hotels and guesthouses in all categories, offering Bronze, Silver, Gold and Platinum (the highest) levels in sustainability and environmental practices. The strict program is based on self assessment, backed of course by TripAdvisor’s guest feedback to keep the green practices in check. Dozens of Greek hotels have joined, and the list is growing steadily.