Ever since humans began to live together in settlements they have felt the need to organise some kind of defence against potentially hostile neighbours. Many of the earliest city states were built as walled towns, and during the medieval era, stone castles were built both as symbols of the defenders' strength and as protection against potential attack. The advent of cannon prompted fortifications to become lower, denser and more complex, and the forts of the eighteenth and nineteenth centuries could appear like snowflakes in their complexity and beautiful geometry. Without forts, the history of America could have taken a very different course, pirates could have sailed the seas unchecked, and Britain itself could have been successfully invaded.

This book explains the history of human fortifications, and is beautifully illustrated using photographs, plans, drawings and maps to explain why they were built, their various functions and their immense historical legacy in laying the foundations of empire.

This is the story of the beginnings of the southern Sierra Nevada, the High Sierra region, from its birth to the historic era. It describes the geologic history, natural history, and prehistoric cultures of this major land feature, which has evolved its own unique plant and animal communities and has nurtured human habitation and growth for thousands of years.