paragraph_text: The Gold Coast Highway in Queensland, Australia links the coastal suburbs of the Gold Coast. in length, the highway runs from near the Pacific Motorway at Pacific Pines to the Pacific Motorway at Tweed Heads. It passes through the numerous popular tourist areas including Surfers Paradise and Broadbeach, a commercial centre at Southport, residential areas, shopping centres and the Gold Coast (Coolangatta) Airport.

paragraph_text: The islands of São Tomé and Príncipe were uninhabited when the Portuguese arrived sometime around 1470. The islands were discovered by João de Santarém and Pêro Escobar. Portuguese navigators explored the islands and decided that they would be good locations for bases to trade with the mainland.

paragraph_text: The indigenous Chamorros settled the island approximately 4,000 years ago. Portuguese explorer Ferdinand Magellan, while in the service of Spain, was the first European to visit the island, on March 6, 1521. Guam was colonized by Spain in 1668 with settlers, including Diego Luis de San Vitores, a Catholic Jesuit missionary. Between the 16th century and the 18th century, Guam was an important stopover for the Spanish Manila Galleons. During the Spanish -- American War, the United States captured Guam on June 21, 1898. Under the Treaty of Paris, Spain ceded Guam to the United States on December 10, 1898. Guam is among the seventeen non-self - governing territories listed by the United Nations.

paragraph_text: Marco Island is a city in Collier County, Florida, United States, located on an island by the same name in the Gulf of Mexico off the coast of Southwest Florida. It is a principal city of the Naples -- Marco Island Metropolitan Statistical Area. The population was 16,413 at the 2010 census.

paragraph_text: The archipelago consists of 36,563 islands, of which 94 are classified as major islands, being larger than 130 km2 (50 sq mi), and cover a total area of 1,400,000 km2 (540,000 sq mi). The islands of the archipelago over 10,000 km2 (3,900 sq mi), in order of descending area, are:

paragraph_text: The Tasman Island, part of the Tasman Island Group, is an oval island with an area of , lying close to the south-eastern coast of Tasmania, Australia. The island is located in the Tasman Sea, situated off the Tasman Peninsula and is contained within the Tasman National Park.

paragraph_text: Denmark's five Danish Gold Coast Territorial Settlements and forts of the Kingdom of Denmark were sold to the United Kingdom and were incorporated into the British Gold Coast in 1850.

paragraph_text: Gloucester Island is a national park in Queensland, Australia, 950 km northwest of Brisbane. It is visible from the town of Bowen. The island was seen and erroneously named "Cape Gloucester" by British explorer James Cook in 1770. The name "Cape Gloucester" has been used informally for areas on or near Gloucester Island.

paragraph_text: Englishman Sir Francis Drake probably located the island on the final leg of his circumnavigation of the world (1577–1580). Further visits by other English explorers followed, and, once Saint Helena’s location was more widely known, English ships of war began to lie in wait in the area to attack Portuguese India carracks on their way home. In developing their Far East trade, the Dutch also began to frequent the island. The Portuguese and Spanish soon gave up regularly calling at the island, partly because they used ports along the West African coast, but also because of attacks on their shipping, the desecration of their chapel and religious icons, destruction of their livestock and destruction of plantations by Dutch and English sailors.

paragraph_text: In fifty years, Gold Coast City has grown from a small beachside holiday destination to Australia's sixth largest city (and the country's most populous non-capital city). Situated within South East Queensland's growth corridor, the Gold Coast is one of Australia's fastest growing large cities, with a 5-year annual average population growth rate to 2015 of 1.8%, compared to 1.5% nationally. Gross Regional Product has risen from A$9.7 billion in 2001, to A$15.6 billion in 2008, a rise of 61 percent. Tourism remains fundamental to Gold Coast City's economy, with almost 10 million visitors a year to the area. In the past the economy was driven by the population derived industries of construction, tourism and retail. Some diversification has taken place, with the city now having an industrial base formed of marine, education, information communication and technology, food, tourism, creative, environment and sports industries. These nine industries have been identified as the key industries by the City of Gold Coast Council to deliver the city's economic prosperity. Gold Coast City's unemployment rate (5.6 per cent) is below the national level (5.9 per cent). The declaration of Southport as the Gold Coast central business district (CBD) and a Priority Development Area (PDA), as well as new investment into the CBD, is driving transformative change and creating new business and investment opportunities.

paragraph_text: In 1482, the Portuguese came to the continent for increased trade. They built the Castle of Elmina, the first European settlement on the Gold Coast. From here they acquired slaves and gold in trade for European goods, such as metal knives, beads, mirrors, rum, and guns. News of the successful trading spread quickly, and British, Dutch, Danish, Prussian and Swedish traders arrived as well. The European traders built several forts along the coastline. The Gold Coast had long been a name for the region used by Europeans because of the large gold resources found in the area. The slave trade was the principal exchange and major part of the economy for many years. In this period, European nations began to explore and colonize the Americas. Soon the Portuguese and Spanish began to export African slaves to the Caribbean, and North and South America. The Dutch and British also entered the slave trade, at first supplying markets in the Caribbean and on the Caribbean coast of South America.

paragraph_text: Acadia National Park is a United States National Park located in the state of Maine, near Bar Harbor. It reserves much of Mount Desert Island, and associated smaller islands, off the Atlantic coast. Initially created as the Sieur de Monts National Monument in 1916, the park was renamed Lafayette National Park in 1919, and was given its current name of Acadia in 1929. Over three million people visited the park in 2016. Acadia is the oldest designated national park area east of the Mississippi River.

paragraph_text: Located in the South Atlantic Ocean on the Mid-Atlantic Ridge, more than 2,000 kilometres (1,200 mi) from the nearest major landmass, Saint Helena is one of the most remote places in the world. The nearest port on the continent is Namibe in southern Angola, and the nearest international airport the Quatro de Fevereiro Airport of Angola's capital Luanda; connections to Cape Town in South Africa are used for most shipping needs, such as the mail boat that serves the island, the RMS St Helena. The island is associated with two other isolated islands in the southern Atlantic, also British territories: Ascension Island about 1,300 kilometres (810 mi) due northwest in more equatorial waters and Tristan da Cunha, which is well outside the tropics 2,430 kilometres (1,510 mi) to the south. The island is situated in the Western Hemisphere and has the same longitude as Cornwall in the United Kingdom. Despite its remote location, it is classified as being in West Africa by the United Nations.

paragraph_text: The Dutch Gold Coast or Dutch Guinea, officially Dutch possessions on the Coast of Guinea (Dutch: "Nederlandse Bezittingen ter Kuste van Guinea") was a portion of contemporary Ghana that was gradually colonized by the Dutch, beginning in 1598. The colony became the most important Dutch colony in West Africa after Fort Elmina was captured from the Portuguese in 1637, but fell into disarray after the abolition of the slave trade in the early 19th century. On 6 April 1872, the Dutch Gold Coast was, in accordance with the Anglo-Dutch Treaties of 1870–71, ceremonially ceded to the United Kingdom.

paragraph_text: Refuge Island is a flat granite island, with an area of about 6 ha, in south-eastern Australia. It is part of the Schouten Island Group, lying close to the eastern coast of Tasmania near the Freycinet Peninsula and is part of the Freycinet National Park.

paragraph_text: Early reports of Europeans reaching this area include those of the Venetian Alvise Cadamosto's voyage of 1455, the 1479–1480 voyage by Flemish-French trader Eustache de la Fosse, and Diogo Cão. In the 1480s this Portuguese explorer reached the Congo River and the lands of Bakongo, setting up the foundations of modern Angola, some 4200 km down the African coast from Guinea-Bissau.

paragraph_text: Portuguese discoveries (Portuguese: Descobrimentos portugueses) are the numerous territories and maritime routes discovered by the Portuguese as a result of their intensive maritime exploration during the 15th and 16th centuries. Portuguese sailors were at the vanguard of European overseas exploration, discovering and mapping the coasts of Africa, Canada, Asia and Brazil, in what became known as the Age of Discovery. Methodical expeditions started in 1419 along West Africa's coast under the sponsorship of prince Henry the Navigator, with Bartolomeu Dias reaching the Cape of Good Hope and entering the Indian Ocean in 1488. Ten years later, in 1498, Vasco da Gama led the first fleet around Africa to India, arriving in Calicut and starting a maritime route from Portugal to India. Portuguese explorations then proceeded to southeast Asia, where they reached Japan in 1542, forty - four years after their first arrival in India. In 1500, the Portuguese nobleman Pedro Álvares Cabral became the first European to discover Brazil.

paragraph_text: European exploration of Sub-Saharan Africa begins with the Age of Discovery in the 15th century, pioneered by Portugal under Henry the Navigator. The Cape of Good Hope was first reached by Bartolomeu Dias on 12 March 1488, opening the important sea route to India and the Far East, but European exploration of Africa itself remained very limited during the 16th and 17th centuries. The European powers were content to establish trading posts along the coast while they were actively exploring and colonizing the New World. Exploration of the interior of Africa was thus mostly left to the Arab slave traders, who in tandem with the Muslim conquest of the Sudan established far - reaching networks and supported the economy of a number of Sahelian kingdoms during the 15th to 18th centuries.

paragraph_text: The islands were first sighted in 1506 by Portuguese explorer Tristão da Cunha; rough seas prevented a landing. He named the main island after himself, Ilha de Tristão da Cunha, which was anglicised from its earliest mention on British Admiralty charts to Tristan da Cunha Island. Some sources state that the Portuguese made the first landing in 1520, when the Lás Rafael captained by Ruy Vaz Pereira called at Tristan for water. The first undisputed landing was made in 1643 by the crew of the Heemstede, captained by Claes Gerritsz Bierenbroodspot.

paragraph_text: The Chamorros, Guam's indigenous people, settled the island approximately 4,000 years ago. Portuguese explorer Ferdinand Magellan was the first European to visit the island on March 6, 1521. Guam was colonized in 1668 with settlers, like Diego Luis de San Vitores, a Catholic missionary. Between the 1500s and the 1700s, Guam was an important stopover for the Spanish Manila Galleons. During the Spanish–American War, the United States captured Guam on June 21, 1898. Under the Treaty of Paris, Spain ceded Guam to the United States on December 10, 1898. Guam is amongst the seventeen Non-Self-Governing Territories of the United Nations.

Question: when did the Portuguese explore the gold coast of the area that the island classified as being in by the United Nations?
Answer: 15th century