Batumi is a seaside city on the Black Sea coast and capital of Adjara, an autonomous republic in southwest Georgia. Batumi, with its large port and commercial center, is also the last stop of the Transcaucasian Railway and the Baku oil pipeline. It is situated some 20 km (12 mi) from the Turkish border, in a subtropical zone, rich in agricultural produce such as citrus fruit and tea. The most visit attractions in and around Batumi are Gonio fortress, a Roman fortification on the Black sea, 15 km south of Batumi, at the mouth of the Chorokhi river; Batumi Botanical Garden, started by professor Krasnov; aquarium and dolphinarium. The old part of Batumi just renewed is also one of the main attractions for tourists.