Khulna (, ) is the third-largest city in Bangladesh, after Dhaka and Chittagong. It is the administrative centre of Khulna District and Khulna Division. Khulna's economy is the third-largest in Bangladesh, contributing $53 billion in gross state product and $95 billion in purchasing power parity (PPP) in 2020. In the 2011 census, the city had a population of 663,342. Khulna is on the Rupsha and Bhairab Rivers. A centre of Bangladeshi industry, the city hosts many national companies. It is served by the Port of Mongla, Bangladesh's second-largest seaport. Khulna River Port is one of the country's oldest and busiest river ports. A colonial steamboat service, which includes the Tern, Osrich and Lepcha, operates on the river route to the city. Khulna is considered the gateway to the Sundarbans, the world's largest mangrove forest and home of the Bengal tiger. It is north of the Mosque City of Bagerhat, a UNESCO World Heritage Site. History Khulna was part of the ancient kingdoms of Vanga and Samatata. It became a part of the Sena dynasty during the 12th-century reign of Ballala Sena, and formed part of the Bagri division of Bengal. During the 14th century, Shamsuddin Firoz Shah was the first Muslim ruler to arrive in the city. Muslim settlements increased during the time of Shamsuddin Ilyas Shah, and many mosques and shrines were established. A Muslim saint, Khan Jahan Ali, acquired a jagir (fiefdom) encompassing a large part of Khulna Division from the king of Gauḍa during the 15th century and renamed the region as Jahanabad. Ali ruled until his death in 1459. After Ali's death, the city became part of the Bengal Sultanate. During the reign of Daud Khan Karrani in the 16th century, Vikramaditya (one of Karrani's chief ministers) obtained a grant in southern Bengal—including Khulna—when Karrani was fighting the Mughals. Vikramaditya established a sovereign kingdom with its capital at Iswaripur (in present-day Satkhira District). He was succeeded by his son, Pratapaditya, who gained preeminence over the Baro-Bhuyans and controlled southern Bengal. Vikramaditya was defeated by Raja Man Singh I, a Hindu Rajput general of the Mughal emperor Akbar, in 1611. Khulna was ruled by autonomous Bengali nawabs until 1793, when the British East India Company abolished nizamat (local rule) and took control of the city. Becoming part of Jessore District in 1842, it became the headquarters of Khulna District (the Khulna and Bagerhat subdivisions of Jessore district,