Most of Perak's abandoned tin mine lakes provide suitable environments for the breeding of freshwater fish. 65% of abandoned mines have been used for fisheries production, with 30% of the fish exported to neighbouring Singapore and Indonesia. To further improve agricultural productivity and meet increasing demand, the state plans to expand the permanent cultivation of vegetables, flowers, coconut, palm oil, durian, and mango, in different areas throughout Perak. The construction sector accounted for 5.6% of Perak's economic growth in 2015, dropping to 4.0% the following year. Development and housing projects represented the sector's major contribution to the state's economic growth. The tertiary sector is Perak's main economic sector. In 2018, the state was the second most popular destination for domestic tourists in Malaysia, after the state of Pahang. Perak's attractions include the royal town of Kuala Kangsar and its iconic buildings, such as the Iskandariah Palace, Pavilion Square Tower, Perak Royal Museum, Sultan Azlan Shah Gallery, and Ubudiah Mosque. The British colonial legacy in Perak includes the Birch Memorial Clock Tower, Ipoh High Court, Ipoh railway station, Ipoh Town Hall and Old Post Office, Kellie's Castle, Majestic Station Hotel, Malay College Kuala Kangsar, Maxwell Hill (Bukit Larut), Perak State Museum, Royal Ipoh Club, St. John Church, and Taiping Lake Gardens. The historical events of the local Malay struggle are remembered in the Pasir Salak Historical Complex. There are also several historical ethnic Chinese landmarks, mainly in Ipoh, the capital. They include the Darul Ridzuan Museum building, a former wealthy Chinese tin miner's mansion; Han Chin Pet Soo, a former club for Hakka miners and haven of shadowy activities; and the Leaning Tower of Teluk Intan. The state also contains a number of natural attractions, including bird sanctuaries, caves, forest reserves, islands, limestone cliffs, mountains, and white sandy beaches. Among the natural sites are Banding Island, Belum-Temengor Forest Reserve, Kek Lok Tong Cave Temple and Zen Gardens, Kinta Nature Park, Matang Mangrove Forest Reserve, Mount Yong Belar, Pangkor Island, Tempurung Cave, and Ulu Kinta Forest Reserve. Recreational attractions include the Banjaran Hotsprings Retreat, D. R Seenivasagam Recreational Park, Gaharu Tea Valley Gopeng, Go Chin Pomelo Nature Park, Gunung Lang Recreational Park, Kinta Riverfront Walk, Kuala Woh Jungle Park, Lang Mountain, Lost World of Tambun, My Gopeng Resort, Perak Herbal Garden, Sultan Abdul Aziz Recreational Park, and Sungai Klah Hot Spring Park.