Geologists call the Lizard a complex. What they mean is the best-preserved exposed ophiolite in the United Kingdom - a piece of ancient ocean floor, including the top of the Earth's mantle, that has been shoved up onto the continental crust. The peninsula is, in literal geological terms, a piece of the seabed pushed inland. Three units make up the Lizard: serpentinites at the top, an oceanic complex in the middle, and a metamorphic basement underneath. The serpentinite here is so distinctive that in 1955 mineralogists named a specific polymorph after the peninsula: lizardite. The Cornish chough, England's rarest breeding corvid, returned to nest on these cliffs in 2001 after a long absence; a quarter of all British flowering plant species grow somewhere on the peninsula. The Cornish heath, Erica vagans, lives here in abundance and almost nowhere else in Britain. The richness comes not from gentleness but from extremes: mild maritime climate, salt-laden gales, alkaline serpentine soils that bake dry in summer and waterlog in winter.

The seaways round the Lizard were known historically as the Graveyard of Ships. The first Lizard light was thrown up by Sir John Killigrew in 1619 at the cost of '20 nobles a year' for 30 years; King James I considered charging vessels for the privilege of passing it, the funding model collapsed, and the tower was demolished. The replacement, built in 1751 by Thomas Fonnereau, still works. The casualty list down those cliffs is long. In 1721 the Royal Anne Galley, an oared frigate, was wrecked at Lizard Point with the loss of around 198 of her 200 crew and passengers, including Lord Belhaven on his way to take up the Governorship of Barbados. In 1807 HMS Anson, a 44-gun frigate, was driven onto Loe Bar a few kilometres north; the disaster inspired Henry Trengrouse to invent the rocket-fired rescue line, which became the breeches buoy. In 1809 the transport ship Dispatch piled into the Manacles rocks on the way home from the Peninsular War, losing 104 men of the 7th Hussars. The 1898 wreck of the SS Mohegan on the same rocks killed 106. And in 1907 came the SS Suevic - the rescue that saved 456 lives and remains the largest in RNLI history.

In 1900 a young Italian engineer named Guglielmo Marconi rented rooms at the Housel Bay Hotel and leased a plot 'in the wheat field adjoining the hotel.' What he built there - the Lizard Wireless Telegraph Station, a wooden hut on the cliff west of the Lloyds Signal Station - is the oldest Marconi station to survive in its original state. From this hut in January 1901 Marconi received a record-distance signal from his transmitter at Niton on the Isle of Wight, 186 miles away. The hut is now restored by the National Trust and looks much as it did the day it earned that record. Eleven months later, on 12 December 1901, from Marconi's other Lizard station at Poldhu Point, a signal travelled across the Atlantic and was received at St John's, Newfoundland. The first transatlantic wireless transmission had been made. Radio, television, satellite communications, the internet - all of it traces a line back to a wooden hut above Cornish cliffs and a kite carrying a wire over the cold air of Newfoundland.

The Lizard's history is not all sea and salt. In 1497 the village blacksmith Michael Joseph - 'An Gof,' the smith - led the Cornish Rebellion from St Keverne, protesting the punitive taxes that Henry VII had levied to fund his war against the Scots. Joseph and his fellow leader Thomas Flamank marched their army to Blackheath outside London, where the rebellion was routed. Both men were hanged, drawn, and quartered. The Lizard has a long memory; their names are still spoken in the parishes here. In 1791, in a more peaceful contribution, the Reverend William Gregor discovered a new element in black sand from a Cornish stream. He called it menachanite, after the local parish. The element is now called titanium. The Solar Eclipse of 11 August 1999 left the UK mainland from these cliffs, the last shadow falling on the southernmost soil before sliding out over the Atlantic. Cornwall has a habit of being where the world starts, or ends, or briefly becomes something else.