On Santa Cruz Island we visited the naturally formed sinkholes known as Los Gemelos (the twins) and a large lava tunnel. This can be walked through, but includes a narrow section to scramble through. We also visited giant tortoises at a private estate where they roam freely, including across roads and the 7km journey to nesting sites in the lowlands.

At the Charles Darwin Scientific Research Centre giant tortoises are hatched to help maintain the specific populations for each island. Older tortoises, which have been rescued worldwide from zoos and private homes, are also housed at the centre. In 1974 a giant tortoise from a species previously thought to be extinct was discovered on Pinta Island and moved to the centre. The last of his kind, he was known as Lonesome George. In 2012 he died (aged around 100) and his species was (again) declared extinct. His body has been preserved for posterity.

In Puerto Ayora, we visited the local shops, fish market and relaxed over a coffee with our guide, who was thankfully on hand to show us the quirks of the Galapagos ATM machine including the card being inserted sideways. Ecuador is the only South American country to use the US dollar as its currency, although with locally designed notes and coins.

This bay is a 20 minute speed boat from the main town of Santa Cruz, Puerto Ayora. On one side is a white sandy beach with surf where marine iguanas feed. The Galapagos marine iguanas evolved from land iguanas because of the plentiful seaweed to feed on. The islands can be dry and food limited for the vegetarian land iguanas.

On the other side is a lagoon on which kayaking is allowed but with a limit of 10 kayaks. The lagoon is home to large number of turtles, rays and marine iguanas. From the kayaks large numbers of resting sharks are seen and some not resting but swimming under and beside the kayaks ! It is breeding season in January and other underwater activities are visible.

The highlights of South Plaza were land iguanas and swallow tailed gulls, which are the only nocturnal gulls.

The snorkelling in tranquil, shallow turquoise waters off Santa Fé allowed us to get close to sharks, turtles, rays and baby sea lions.

Bartholomé is a newer island and its formation is more obvious as plant and animal life is in the early stages of forming. The peak is reached by 346 wooden steps. The spectacular view from the top was featured in the film ‘Master and Commander’, however none of the actors came to the island and locals were used, to be replaced by CGI versions of Russell Crowe and friends.

Chinese Hat is named after its shape and was another opportunity to snorkel, the highlight of which was swimming with reef sharks.

The Pikaia Lodge is on Santa Cruz Island, which has a population of 23,000 out of the total in the Galapagos of 25,000. The lodge has 14 rooms and is the only hotel with its own yacht. In a six day stay guests have three full day navigations. On each trip we were in a group with 2-4 other guests and our guide, Mario. Due to the strict regulations there was never more than one other group on each island but generally we were the only group.

Our first trip was to North Seymour and Mosquera. The islands usually have two names; one Spanish and one English, either may be the official name. The English names have naval connections eg the English name for Santa Cruz is Indefatigable. South Seymour is officially named Baltra.

North Seymour has blue footed booby birds and great and magnificent frigate birds. Mario, our guide, told us that we were lucky to see the mating ceremony of the boobies, known as the booby dance.

The island hike was followed by snorkelling and a beach walk on Mosquera Islet to see sea lions. A feature of all the islands is the approachability of all the animals, birds and sea life as they have not needed to adapt to human behaviour.

The Galapagos Islands are an archipelago of 21 islands formed by volcanic eruptions as the Nazca tectonic plate moves at a rate of 7cm per year (the same rate as human nails grow) from north east to south west over a lava hotspot in the earth’s crust. This means that the western islands are “younger” – Fernandina, less than 500,000 years old, versus those in the east, upto 3.5 millions years old. The islands have never been attached to a continent and are separate from each other, giving rise to their unique eco-systems.

The islands were first discovered in 1535 and were used by whalers and pirates in the 16th and 17th centuries for safe harbour and a source of fresh meat in the form of giant tortoises, which would be kept alive on board ships for upto a year in forced hibernation. The whalers and pirates also bought unwanted visitors in the form of rats, cats, dogs, goats and pigs which continue to have a negative impact on the endemic species.

In 1832 Ecuador, the nearest country, claimed the islands. Ecuador began populating the islands in the 1920s and 1930s by giving free land to people seeking a new life based on fishing and agriculture. In 1959 the islands became a National Park, which covers 97% of the land with the other 3% owned privately by the population of 25,000 who now rely on tourism for a living.

In 1835 the Galapagos’ most famous visitor arrived and stayed for five weeks, Charles Darwin, on board The Beagle. He noticed the differences between the four species of mockingbirds found on different islands. This formed the basis of his theory of evolution in his book The Origin of Species published in 1859. He did not focus on the 17 types of what are now known as Darwin Finches as he did not recongise them as a group.

The Galapagos are now subject to strict regulations to protect the unique environment. Tourist numbers and travel to each island (numbers and times slots) is strictly regulated and visitors must be accompanied by a qualified guide. Citizenship is only allowed by birth or after 10 years of marriage. The rangers control invasive animals and plants (eg blackberries) and conservation is in place to protect species under threat of extinction. Since humans arrived the population of giant tortoises has reduced by 90% and four of the known species of 17 have become extinct.