Lonesome George has been described as the world's rarest creature - he is the last remaining survivor of a subspecies of giant tortoise.
Saving the tortoises of the Galapagos
Since the 17th Century, populations of giant tortoises have declined dramatically. But the Charles Darwin Research Station has used captive-breeding programmes to boost numbers, and over the past few decades thousands have been released back into the wild.
Tourism shifts from sea to land
In the 1960s, tourism was mostly ship-based - visitors would stay onboard and alight at sightseeing spots of choice. But there has since been a huge growth in air traffic, and many people now make Santa Cruz their base. Conservationists are worried about the impact this will have on the island.
All this week, BBC News will be reporting from the Galapagos Islands.
Text by David Shukman, photographs by Mark Georgiou and video by Rob Magee
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