Coral reef islands and atolls. The reef face is the zone above the reef floor or the reef drop-off. This zone is often the reef's most diverse area. Coral and calcareous algae provide complex habitats and areas that offer protection, such as cracks and crevices. Invertebrates and epiphytic algae provide much of the food for other organisms. A common feature on this forereef zone is spur and groove formations that serve to transport sediment downslope. The reef flat is the sandy-bottomed flat, which can be behind the main reef, containing chunks of coral. This zone may border a lagoon and serve as
Open-air Water Museum Open-air Water Museum The Open-air Water Museum () is located in the city of Edessa, Central Macedonia, Greece. In the early 20th century there were many water-powered workshops in the city. In 1991 the Municipality of Edessa decided to improve and develop the Mills area, the Kannavourgio and the ‘Estia’ works, by establishing an open air, water-power museum, and creating recreation areas. The Open-Air Water Museum, which opened early in 2000, aims to acquaint visitors with the history of water-power from the workshops of pre-industrial times up to the early 20th century. The museum consists of the buildings of the