Mercusuar iku wangun yasan menara minangka didadèkaké sumber cahya ing dhataran kang dhuwur uga duwé mupangat kanggo mbiyantu navigasi kapal sagara. Sumber cahya kang digunakaké jinisé wujud warna saka lampu nganti lensa uga  (ing mangsa biyèn migunakaké) geni.

Karana kamajuan jaman kang sansaya maju navigasi kapal sagara dibiyantu déning GPS, cacahé mercusuar ing donya ngalami kamudunan saka 1.500 mercusuar.Mercusuar duwé mupangat dadi pertanda ing laladan-laladan bebayan kaya ta karang utawa laladan sagara kang cétek

Salah sijiné mercusuar kang paling misuwur ing donya ya iku Pharos ing Alexandria, kang kagolong dadi pitu kajaiban donya Pitu Kaajaiban Donya Kuna.

Pranala njaba 

 The Lighthouse Directory Research tool with details of over 9000 lighthouses and navigation lights around the world with photos and links.
 Lighthouse Explorer Website  The Lighthouse Explorer Database, with over 7500 lighthouses listed in searchable format, with information, photos, maps and other information
 The WWW Virtual Library: The World's Lighthouses, Lightships & Lifesaving Stations  Links to a variety of lighthouse related resources on the web
 Guide to Lighthouses A growing gallery of Lighthouses images and history
 Lighthouses and beacons on Planete-TP
 Volume 7, US Coast Guard Lightlist in PDF Format.