In 1875, General Garibaldi, the legendary military hero of Italian unification, left his island retreat in the Mediterranean for Rome. His battle cry no longer required, he was pursuing a mission that would become an obsession in his old age: to divert the River Tiber from Rome.

Through this forgotten episode, Daniel Pick explores Garibaldi's passionate attachment to Rome and to Italy. In the bitter debate that ensued many myths were laid bare, and prevailing medical, social and political anxieties about the future of the state were exposed.

The flood-prone Tiber had caused havoc, disease and death throughout history. In the capital, the General sought to replace it with a Parisian-style boulevard that would be a wonder of the modern world. But behind his florid promise to revitalise 'Italy' lay a complex and shadowy history, including a traumatic event felt by Garibaldi as the defining tragedy of his life: the loss of his wife Anita. Despite himself, he became embroiled in the political labyrinth of Rome and a drama of thwarted ambition, grand illusion and disillusionment, whose significance was not lost on Garibaldi's later admirer, Benito Mussolini, another self-styled redeemer of the Eternal City and the fever-ridden marshes of Italy.