Odessa or Odesa is the third most populous city of Ukraine and a major tourism center, seaport and transportation hub located on the northwestern shore of the Black Sea. Odessa is also an administrative center of the Odessa Oblast and a multiethnic cultural center. Odessa is sometimes called the "pearl of the Black Sea," the "South Capital" (under the Russian Empire and Soviet Union), and "Southern Palmyra".
The predecessor of Odessa, a small Tatar settlement, was founded by Hacı I Giray, the Khan of Crimea, in 1440 and originally named after him as "Hacıbey". After a period of Lithuanian control, it passed into the domain of the Ottoman Sultan in 1529 and remained in Ottoman hands until the Ottoman Empire's defeat in the Russo-Turkish War of 1792.
In 1794, the city of Odessa was founded by a decree of the Empress Catherine the Great. From 1819 to 1858, Odessa was a free port. During the Soviet period it was the most important port of trade in the Soviet Union and a Soviet naval base. On 1 January 2000, the Quarantine Pier at Odessa Commercial Sea Port was declared a free port and free economic zone for a period of 25 years.
During the 19th century, it was the fourth largest city of Imperial Russia, after Moscow, Saint Petersburg and Warsaw. Its historical architecture has a style more Mediterranean than Russian, having been heavily influenced by French and Italian styles. Some buildings are built in a mixture of different styles, including Art Nouveau, Renaissance and Classicist.
Odessa is a warm-water port. The city of Odessa hosts both the Port of Odessa and Port Yuzhne, a significant oil terminal situated in the city's suburbs. Another notable port, Chornomorsk, is located in the same oblast, to the south-west of Odessa. Together they represent a major transport hub integrating with railways. Odessa's oil and chemical processing facilities are connected to Russian and European networks by strategic pipelines.