Archaeological sites, by definition, are places where the living wander carelessly among the concentrated shades of the dead.

They are like deep wells, where the visitor stands in the light of day and his or her imagination teems with images of how the area might have looked when its ancient occupants were alive, but underfoot run dark corridors and invisible rivers of blood.

These are places where people lived, created, loved, fought, connived, achieved, won, lost and died.

The presence of the dead is even stronger here than in cemeteries, because their shade extends among the ruins of daily life, and because today’s generations roam among walls that once sheltered dreams and murder.

The awe one feels on seeing the plaster casts of Pompeii’s dead — who fell in their vain effort to survive — is greater than that which cemeteries evoke, where the dead have been tidied up and crowned with tears and honors. Within the space where the dead have lived one feels more strongly the vanity of life, the brutality of the inevitable.

In archaeological sites, scholars poke about in the dust and ash and the unknown, looking for some sign of those who once enjoyed briefly the same light, as if we today are made of some different, tougher stuff.

Among the stones and broken artifacts — clay jars, combs, swords and works of art — we recognize fragments of life. But archaeological sites are, inevitably, investigations into causes of death, usually on a grand and violent scale.

At Mycenae, Heinrich Schliemann sought the protagonists of the bloody tale of the House of Atreus. At Troy, a few years earlier, he found a prehistoric city whose destruction in war gave humanity the greatest poem it has known.

At Akrotiri on Thera (Santorini), Spyros Marinatos looked for the roots of the destruction of Minoan civilization on nearby Crete and found an equally important world preserved in the layers of volcanic dust and detritus that destroyed but also preserved an ancient city till our days. In a double tragedy, the necessary and inspired effort to protect the antiquities for future generations caused the death of a visitor to the site on Friday, when part of the high-tech roof collapsed suddenly.

In 1979, the archaeologists Yiannis and Efi Sakellaraki made the sensational discovery of a human sacrifice on the windswept shrine at Anemospylia near Archanes on Crete. There, it appeared that a priest and priestess died when the building collapsed on them soon after they had slit the throat of a young man, in a vain effort to avert the greater harm of the great earthquake that leveled Crete in 1700 BC. Every city, every site that is dug up reveals signs of war, earthquake and fire. Man’s destiny is death, usually violent and unexpected, like that which stained the sand of Santorini with blood again. If one considers that Marinatos himself died in a fall at the site, one recalls Elias Canetti’s argument, in “Crowds and Power,” of the enmity the dead feel for the living. But perhaps the explanation is best found in Homer’s Odyssey. When Odysseus travels to the underworld, only after he has given the wretched shades of heroes blood can they muster the strength to talk to him. And so Akrotiri reminded us that though the bodies of its original inhabitants may not have been found, their city was destroyed violently and they died nearby or in exile. In our sorrow at the death of the visitor whose interest in antiquities put him in harm’s way, beyond our concern at the safety of the ruins themselves, we see that Friday’s tragedy was another episode in the long and unpredictable adventure of Akrotiri.

Today the shades of Thera tell us that we may believe that we are tourists, or that the roofs we build will last for centuries, but the rules of life and death that applied to them apply to us as well.