The Canary Islands are estimated to be 30 million years old, which is relatively young by geological standards.
Carbon dating has placed the earliest settlement at around 200 BC, although earlier settlement is possible. The conquering Europeans' 15th-century descriptions of locals refer to tall and powerfully built people with blue eyes and long fair hair. These people called themselves Guanches, from guan, meaning 'man', and che or achinch, meaning 'white mountain', in reference to the snow-capped Teide volcano. Theories regarding the Guanches range from them being Celtic immigrants from mainland Spain or Portugal, to Norse invaders. Berber immigrants from nearby Saharan Africa almost certainly inhabited some of the eastern islands, where place names bear a striking resemblance to Berber tribal languages. Occasionally, however, blue eyes and fair hair crop up among the Berbers as well, so the Guanches' origin is still open to question.
The Guanches relied on limited farming, herding, hunting and gathering for their subsistence; the majority of them lived in caves. The first vaguely reliable account of European arrival dates from the late 13th or early 14th century, when the Genoese captain Lanzarotto Malocello came across the island that would later bear a version of his name: Lanzarote. A host of dreamers, looking for the legendary Río de Oro (River of Gold), missionaries and slavers passed by or came to stay, but it took the Portuguese-Italian mission of 1341 to finally put the Canaries on the map.
The first Europeans to attempt to conquer the Guanches were Normans from France in 1402, and the final campaigns ended around 1495 under a Galician soldier of fortune. The century saw massacres, warfare and Guanches sold into slavery; less than a century later, their language had all but disappeared. Survivors married the invaders, converting to Christianity and taking Spanish names.
Spain's control of the islands did not go unchallenged. First, Moroccan troops occupied Lanzarote in 1569 and 1586, then Sir Francis Drake tried a little gunboat diplomacy off Las Palmas in 1595. A Dutch fleet reduced Las Palmas to rubble in 1599, then in 1657, the Brits, under Admiral Robert Blake, annihilated the Spanish at Tenerife.
Spain managed to hang on though; the Canaries were declared a province of Spain in 1821, with Santa Cruz de Tenerife the official capital. This provoked the inhabitants of Gran Canaria to demand that the province be split in two - it was, for a short and unsuccessful period in the 1840s. Several agricultural commodities followed boom-bust cycles on the islands: sugar cane, wine and then cochineal for making dyes, followed by bananas and, to a lesser extent, tomatoes and potatoes.
The WWI British maritime blockade of Europe destroyed the banana trade. Canarios voted with their feet and fled the poverty in droves for a new life in Latin America.
The short period of hope that followed WWI was dashed when Spain fell into civil war in 1936. In March of that year, the Spanish Republic transferred General Franco to the Canaries, under the (well founded) suspicion that he was involved in a plot to overthrow the government. Franco seized the islands in July, then flew to Morocco to continue the fight, leaving the Nationalists to round up Republican sympathisers on the islands.
The Canaries suffered from the same post-war misery as Spain. Again, thousands fled, although this time clandestinely and mainly to Venezuela. In the 1950s, 16,000 people left the country; a third of those who attempted the journey perished in leaky boats. By the early '60s, Franco decided to throw the country's doors open to sun-starved tourists. Millions of sun-seeking hedonists now flock to the islands annually.
Coalición Canaria played a large role in the right wing Partido Popular's win at the general elections in 1996. They lent their support to the government under the condition that consideration be given first and foremost to their needs, putting the interests of the islands before any national considerations.
Having been granted the status of a comunidad autónoma(autonomous region) in 1982, the Canaries have been leveraging their political strength in recent times. The current ruling party is the nationalist liberal Canarian Coalition, headed by Adán Martín Menis. There's considerable nationalist sentiment on the islands, and travellers shouldn't be too surprised to see the occasional 'Spanish go home!' grafitti about the place.
These days, the islands are most often in the news because of the thousands of sub-Saharan African immigrants that arrive in precarious (and for the most part illegal) conditions to their shores.