Yacht and watchtower at entrance to Mgarr ix-Xini coastal inlet, island of Gozo, Malta, Mediterranean, Europe

O'Brien's Tower, Cliffs of Moher, Cliffs Coastal Walk, County Clare, Munster, Republic of Ireland, Europe

Riserva Naturale di Punta Bianca, Palma di Montechiaro, Agrigento, Sicily, Italy

Moher Tower, Cliffs Coastal Walk, County Clare, Munster, Republic of Ireland, Europe

Beachgoers crossing a lagoon formed by the low tide, and detail of a watchtower in Cacela Velha, Algarve, Portugal, Europe

Finisterre lighthouse, Cape Finisterre, Finisterre (Fisterra), La Coruna, Galicia, Spain, Europe

Pacific Coast, Zuma beach, California, United States of America, North America

Santa Barbara beach and Santa Barbara pier, California, United States of America, North America

The palm-fringed Torre della Polveriera, a historic stone watchtower in Piazza della Juharia atop the Old Town walls, Alghero, Sassari, Sardinia, Italy, Mediterranean, Europe

Chiesa Santa Margherita di Antiochia church, view from watchtower at Castell Doria, Vernazza, Cinque Terre, UNESCO World Heritage Site, Rivera di Levante, Provinz La Spazia, Liguria, Italy, Europe

View of Lifeguard Watchtower on Venice Beach, Los Angeles, California, United States of America, North America

View of lifeguard watchtower at Playa de Palma at sunset, S'Arenal, Palma, Majorca, Balearic Islands, Spain, Mediterranean, Europe

Hikers on the Cami de Cavalls, hiking trail GR 223, with the headland and watchtower Es Colomar in the background, s'Albufera des Grau Natural Park, Menorca, Balearic Islands, Spain, Mediterranean, Europe

View of Lifeguard Watchtower on Venice Beach, Los Angeles, California, United States of America, North America

Santa Cruz Beach, Santa Cruz, California, United States of America, North America

Santa Cruz Beach, Santa Cruz, California, United States of America, North America

Santa Cruz Beach, Santa Cruz, California, United States of America, North America

Royal Guernsey Golf Club, Martello towers, watch towers and fortified towers built in the 17th century, next to the fairways, at Pembroke bay in the northeast of the Channel Island of Guernsey, Europe

Rescue tower and rescue boat on the beach, evening mood, Adriatic Sea, Italy, Europe

Rescue tower and rescue boat on the beach, Adriatic Sea, Italy, Europe

Sunset, Watchtower Talaia d'Albercutx, Cap Formentor, Port de Pollença, Serra de Tramuntana, Majorca, Balearics, Spain, Europe

Watchtower for lifeguards in the sand dunes of Maspalomas, Gran Canaria, Canary Islands, Spain, Europe

Aerial view, Albercutx watchtower, Talaia d'Albercutx, rocky cliffs and sea, Cap Formentor, coastal landscape, evening mood, Pollenca, Majorca, Balearic Islands, Spain, Europe

Martello towers, watch and guard towers from the 17th century found along the coastline, here Tower No. 5 at Pembroke Bay in the northeast of Guernsey, Channel Islands, Europe

Genoese watchtower, rocky coast of Porto, Gulf of Porto, Corsica, France, Europe

O'Briens Tower, Cliffs of Moher, County Clare, Ireland, Europe