Oviši lighthouse in Kurzeme is deemed the eldest working navigational structure in Latvia, built in 1814. The lighthouse tower is 37 m high. It is a double-cylinder structure – the diameter of the tower is 11.5 m, but inside of the stone wall is another tower with a diameter of 3.5 m. In the 18th and 19th century, lighthouses if this type were used in Europe also as defence structures in case of enemy attack. Once, there was also an illumination apparatus with searchlight lenses run by a clock mechanism, but it was transported to Russia in 1915. German occupation authorities installed a new lighting equipment with acetylene burner, which was used to 1961. White rotary light, which is visible 7.5 miles far, flashes every 7.5 seconds. Next to the previous exhibits – navigation objects, which were used at different periods by various lighthouses, also in Oviši –, the lighthouse now features new interactive exhibits. The navigation history demonstrated at the lighthouse museum catches your eye, and invites to listen and touch it. From the top of the lighthouse, the nearby Miķeļbāka lighthouse, the highest lighthouse in the Baltic states (62 m), is visible on the coast and the youngest lighthouse in Latvia, the Irbe lighhouse (1986), is seen in the sea.