Tenerife's recorded history stretches back to around 200 BC. The earliest known settlers were known as the Guanches, an offshoot of Berbers from North Africa, who are believed to have emigrated to the Archipelago in around 1000 BC. At some point between 1494 and 1496, Tenerife was conquered by the Spanish, the last of the Canary Islands to fall. As with all the islands, the Spanish enslaved many of its Guanche inhabitants, especially those who chose to resist Spanish occupation. In the 1520s, sugar cane was introduced to the island, a labour intensive product which requires a lot of work, the slave trade was formed around the cultivation of this crop. Because Spain ruled both Latin America and The Canary Islands, the relationship between the two is strong to this day. When the New World, America, was being colonised, many of the Spanish expeditions stopped at Tenerife for supplies. Many of Tenerife's residents were signed up to work on the crews of the ships, others boarded in the hope of travelling to a better life. Between them, they helped Tenerife play a major role of the colonisation of the Americas. This began a long tradition of links between The Canary Islands and the Americas, with the populations of both settling in each other's land, some in the effort to colonise the New World, others to introduce successful cultivation techniques for newly discovered crops such as cocoa and tobacco. During the 19th and 20th Century, emigration from Tenerife to the Americas increased as a result of a poor economic landscape in the Canary Islands with people struggling to find work and earn and living. Between 1833 and 1927, Santa Cruz de Tenerife was the capital of the Canary Islands. But in 1927, the government ordered that the capital be shared with Las Palmas. The label of 'capital city' is shared to this day. Large scale tourism to Tenerife started in the 1890s, when visitors from Spain, England and Northern Europe started arriving to take advantage of the beautiful landscape and reliably warm weather. The Spanish Civil War, between 1936 and 1939, left much of Tenerife in ruins. Many of its inhabitants, distressed from the emotional and physical aftermath of war, fled to Cuba and other Latin American countries. Modern day Tenerife is a thriving island. With around 5 million visitors each year, tourism remains its largest industry. However, the island also plays a key role in environmental and scientific research; various companies and establishments have a presence on the island because the natural conditions of the landscape and weather make it the perfect testing ground for environmental and sustainable innovations.