One of the best books I've read is Peter Ackroyd's London: the Biography.
Ackroyd starts with prehistory. His first chapter is "The Sea!" and he notes how the site of our capital some fifty million years ago was covered by the great waters. "The waters have not wholly departed, even yet," and Ackroyd points out that creatures that lived some 50 million years ago in the seas that covered what is now the South East of England may be seen in the stones that were used to build London and her monuments... "there are ancient oyster shells within the texture of Mansion House and the British Museum. Seaweed can still be seen in the greyish marble of Waterloo Station, and the force of hurricanes may be detected in the "chatter-marked" stone of pedestrian subways. In the fabric of Waterloo Bridge, the bed of the Upper Jurassic Sea can also be observed. The tides and storms are still all around us, therefore, and as Shelley wrote of London 'that great sea ...still howls on for more'...The London clay can yield more tangible evidence: the skeletons of sharks...the skull of a wolf in Cheapside, and crocodiles in the clay of Islington."
In 1682 Dryden recognised this now forgotten and invisible landscape of London:
Yet monsters from thy large increase we find
Engender'd on the Slyme thou leav'st behind.
Eight years after Dryden wrote those lines, in 1690, the remains of a mammoth were found beside what has since become King's Cross.
It's a superb study - historian meets novelist meets poet. Someone once said that dining with Ackroyd was like "dining with the British Museum". A.N. Wilson said of London: "It would be no exaggeration to say that Peter Ackroyd's "biography" of our capital is the book about London. It contains a lifetime of reading and research...but this huge book is light and airy and playful...(He) leads us on a journey both historical and geographical, but also imaginative. Every street, alley and courtyard has a story, and Ackroyd brings it to life for us."
I once, to the bemusement of my friends who were off to Harrods and Harvey Nics, spent a day exhausting myself wandering around London, Ackroyd's big book clutched to my bosom. It was a heavy and cumbersome tome to carry around as a "guide", but well worth the effort. I spotted things I should otherwise have missed. Dining with Ackroyd alas I'll never manage, but I could still walk with him - or rather trot behind him, gob-smacked at his erudition.