These are the godless islands, the lava lumps likened to Hell by lapsed clergyman and creationist Charles Darwin. "Nothing could be less inviting than the first appearance," he wrote after landing in the Galápagos in 1835. "The country was compared to what we might imagine the cultivated parts of the Infernal regions to be."
His words still ring true on arrival at Baltra airport, the World War II US Air Force base turned gateway to the Galápagos. First appearances are underwhelming. After flying more than a thousand kilometres from the Ecuadorian coastal city of Guayaquil, we alight at an arid scrap of baking red earth. The highlight of this dreary spot is a sea lion sprawled on the jetty where we board Zodiacs bound for the Silver Galapagos, our floating observatory for the coming week.
These are also the enchanted islands, las islas encantadas, so nothing is quite as it seems. That unremarkable rocky platform visible from the starboard deck? It's Daphne Major, the island whose resident finches have been monitored and measured meticulously for four decades to prove beyond doubt that natural selection is not some glacial process, as Darwin suggested, but a dynamic development visible from one season to the next. Far from being just a plain island in the Pacific, Daphne Major is a crucible of modern evolutionary understanding.
There are 13 large islands and six smaller ones in the archipelago, and each is at least as surprising as Daphne Major (except Baltra, which really is as bleak as it looks). But there's no need to pack a working knowledge of Darwin's theory on the origin of species to appreciate the significance of the Galápagos Islands' unique life forms. You just need to understand, as onboard naturalist Desiree Cruz puts it so neatly, that "each island is a little world by itself".
"Even though we can say we are going to see iguanas, finches and boobies each day, each island is different," Cruz says. For example, each has its own species of giant Galápagos tortoise - except Isabela, which supports five distinct subspecies, and the four islands where the tortoise has become extinct. (The famous Lonesome George, who died in 2012, was the last of his Pinta Island posse.)
Once this singular reality is grasped, the islands of the Galápagos become very fascinating indeed. Every day brings new discoveries, and even the most barren-looking islands brim with life. On an outing to the forbidding, iron-rich Rábida, where sand and rock are the colour of dried blood, brilliant Panamic starfish glimmer on the sea floor metres below and two eagle rays mate so violently that they soar out of the water, in flagrante delicto. When I snorkel over its submarine rocks cloaked in a brocade of corals, dense curtains of tropical fish throng me and dazzle in the sunlight. A bark from above signals a Galápagos penguin, fluffing and drying itself on a finger of rock flanked by three inky-black marine iguanas ("imps of darkness", Darwin called them) and vibrant red Sally Lightfoot crabs. It could be a postcard. I am dazzled below the sea and delighted above it.
It's not possible to visit the entire archipelago in a week. Our itinerary on the newly christened Silver Galapagos - a 1990 Italian-built ship rebadged by Silversea a year ago - takes us on a sweep of 435 nautical miles around the north and central islands. In natural history terms, that means no hammerhead sharks or flamingos but a surfeit of sea lions, boobies and big colourful lizards, fabulous underwater worlds, and even the odd penguin.
The Galápagos National Park Service, which controls 97 per cent of this World Heritage-listed wonder, dictates the visiting schedule of every ship in order to limit the human impact on this precious archipelago. The upside of strictly regulated visits is that, in most instances, we have each site to ourselves. Excursions manage to feel unique and privileged despite the fact that the Galápagos now receive about 200,000 visitors a year.
Surging tourist numbers have not dimmed the enthusiasm of the welcoming committee on Española Island. A floppy honour guard of sea lions awaits as we step onto the crunchy sands at Punta Suárez. Mockingbirds dart forward like deranged emissaries, fussing about our legs and gibbering away as if we share a common language.
"Animals don't know a thing about rules here," explains naturalist Xavier ("You can call me Harvey") Suarez as he leads us on an action-packed tour. Look, over here! It's a sea lion placenta! Suarez says there must be a week-old pup in the nursery in front of us, but we can't spot it in the tumble of furry bodies surfing the shallows.
There is so much to see around every corner, over every crest, that we are constantly sidetracked and waylaid and amazed. Pretty Galápagos doves decked out in bright blue eyeliner peck for seeds at our toes; a crèche of iguanas reclines on sunbaked boulders; Christmas iguanas in their blood-red and copper-green mating livery contrast vividly against the jet-black rockery of the Española shoreline. With their craggy, fierce features and showgirl colours, they look like very ugly drag queens.
Last stop before heading back to the Zodiacs is the "albatross international airport", a landing strip of ferrous red stones where waved albatross chicks take their first tentative flights off the edge of a cliff. The airport is out of season when we visit. As a consolation, a sole Galápagos hawk poses at the top of a rock stack above the ocean, a light gale buffeting his dappled coat.
It's a full day by any measure, but it's not over yet. That evening, diners on the Grill Deck are disturbed by a melée below. Ship spotlights illuminating the surface are a beacon for fish, and they in turn attract sea lions keen for an easy feed. The predators herd their quarry into the ship's hull at speed, and then gorge on the stunned seafood feast. Sharks lurk on the fringes for easy pickings. It's brutal and thrilling to watch, a bit like living out an Attenborough documentary.
Silversea has been at the top of the food chain since it arrived here last September as part of the Italian line's expansion into expedition cruising; the company now has three expedition ships in its fleet. For anyone wanting to see the Galápagos in style, this refurbished 100-passenger vessel would be their natural selection. The upscale cruise company promised to bring impeccable Italian service and style to these remote islands, though the reality on my voyage doesn't always live up to this expectation.
To be fair, the Ecuadorian Government imposes strict quarantine and sourcing regulations on cruise operators that prevent Silversea from offering "the full complement of our renowned service options", as the vice president of fleet operations, Christian Sauleau, tells passengers in a typed note left in some cabins. Translated, this means restricted menus (no raw meat, no berries, no French cheeses), no Bulgari toiletries in bathrooms and - gasp - no free-flowing Champagne, usually a hallmark of Silversea life.
The absence of such luxuries would not have been so surprising had guests known in advance; the Silversea website made no mention. It's not until passengers settle into their mahogany veneer and brass-trimmed cabins that they find Sauleau's letter welcoming them aboard and breaking the bad news. "Cruise ships operating in the Galápagos Islands are unable to offer their guest the normal array of delights you might be accustomed to on other Silversea vessels," he advises.
The result is an overwhelmingly Ecuadorian - rather than chic European - experience. This has its upsides, from the super-fresh seafood served in the two restaurants to the 70-strong crew whose presence lends a very local, very friendly tone to days at sea.
Still, the slip in ship standards does not go down well with Silversea veterans on this cruise. Many guests are unimpressed with life onboard. Faulty cabin fittings and air-conditioning are just two of the complaints I hear. This is my third Silversea cruise and it doesn't compare well to the sharper, more seamless operations of the line's other vessels I've been aboard, even the flagship expedition ship Silver Explorer.
But the only quibbles are onboard. Never outdoors.
We spend a morning on Bahía Gardner picking our way between sea lions splayed on the beach in all sorts of inelegant poses, oblivious to our presence. They are fond of spooning each other, which is charming, but they also sneeze and cough productively, revoltingly, which is less charming.
On a visit to the privately owned Manzanillo ecological reserve in the steamy highlands of Santa Cruz, we spot six giant tortoises before we even get off the bus. By the end of our walk through the lush parklands our tortoise tally is 73. Ridiculous.
There is something primitive and prehistoric about the Galápagos, especially in the way its creatures are so fearless of humans. They walk beside us, clamber towards us, and fly alarmingly low over our heads.
It borders on the Jurassic. "Antediluvian", Darwin called it.
On the island of Seymour Norte, after a brush with a reef shark, I have possibly the most delightful man-meets-animal interaction of my life. I'm snorkelling among spotted eagle rays and Moorish idols trailing their veils behind them like genies when a pretty face with Mila Kunis eyes pops up in front of my mask. "Hola!" she seems to say, and it's clear she wants to play. So I pull off my snorkel and plunge underwater, doing my best to twirl and shimmy like I imagine a sea lion might do. My amiga slices away from me, but is back in a flash, and there begins a beautiful if fleeting friendship. We writhe and dip and spin underwater - me taking regular breathers - in a cross-species ballet that leaves other passengers enthralled."It was like it mimicked everything you were doing," one marvelled afterwards.
This exhilarating encounter makes me sick from all the saltwater I've swallowed, but also slightly wistful. I wonder if I, too, could adapt permanently to life in these enchanted islands. Gills would be a fine start.