Attenborough opens the series at the Dead Sea, where the hot climate and intense evaporation mimic conditions that were replicated on a much larger scale when the newly-formed Mediterranean basin dried out. Around 5.5 million years ago, the Atlantic flooded the basin, allowing marine life to recolonise the new sea. Mountains became islands: some of them volcanic, others formed of limestone. Common species marooned on these islands evolved into new varieties.

Attenborough explores the influence of the first Mediterranean civilisations, placing the symbolism of the bull at the centre of his narrative. Cave paintings in France and Spain and Egyptian hieroglyphs both reveal cultures that revered the wild bull for its fertility and strength.

Crop cultivation began in the Nile Delta, but the Minoans were the first to harvest olives, using oxen-powered mills to crush them. They were also skilled fishermen, whose traditional methods for catching octopus and tunny are still practised by modern North Africans. Attenborough explains how Cretan men pitted themselves against bulls in specially-built arenas. The Romans were passionate hunters, using wild animals ransacked from their Empire for entertainment, but they also held the bull in special regard.

The relationship between man and horse has a long history in the Mediterranean region. A passion for horses spread west from Central Asia, but took a while to become established as a pastoral way of life returned. The Roman Empire was replaced by marauding Huns, Visigoths and Vandals. In the seventh century, Arabian cavalrymen took Jerusalem and arrived in Spain to spread the word of the Qur'an. They established bases at Córdoba and Granada, bringing orange trees and peacocks for the gardens of their impressive mosques. The Arabs brought their falconry skills too.

Attenborough visits the impregnable Krak des Chevaliers in Syria to discuss the Crusades. Black rats carried on the retreating Christian army’s ships spread plague through Europe, killing a third of the population. During the Middle Ages the forests of Southern Europe were cleared. Attenborough discusses the deforestation caused by Spanish Merino sheep grazing and the Venetian shipbuilding industry. Despite the advent of the internal combustion engine, horses still play an important role in European culture. The final scenes show thoroughbreds racing at Newmarket and a performance by the Spanish Riding School in Vienna.

The final episode examines man's impact on the Mediterranean during the twentieth century. Attenborough dines on red soldierfish in Cyprus, one of a hundred or so species to have colonised the Mediterranean from the Red Sea, via the Suez Canal. Other invaders have been less welcome. The Phylloxera aphid from North America attacked French grapevines, and only by importing insect-resistant rootstock from the USA was a total catastrophe averted.

The growth of tourism has led to uncontrolled development of hotels and marinas, squeezing out natural inhabitants of the coast such as Mediterranean monk seals and loggerhead turtles, who come ashore to lay their eggs. The sea is in danger of becoming barren due to overfishing and pollution. Attenborough dives beneath the surface to demonstrate the difference between a thriving seagrass ecosystem and one smothered in sedimentation from untreated sewage.