For a biologist this is not so "unknown", a specialized botanist might even tell the species.
All I can contribute is that this plant belongs to the genus Ornithogalum. There are countless species all over the world, many of them difficult to identify. One of the more wide-spread English common names is "Star-of-Bethlehem", in German language we simply call it "Milk-Star" (literal translation).
Don't try to taste it, parts of the plant are quite poisonous.
as Harry S. says, Orthnithogalum umbellatum. The Star of Bethlehem. Europe has three species of Orthnithogalum, and this is the most common.
You are on a island that is famed for its flora, even more so than Crete, and that is spectacular to put it mildly. Go into the Troodos Mountains and see just what I mean.
Panos, these flowers we both now know, are called "orthnithogalum umbellatum" or "Star of Bethlehem". Thank you Harry S! This year's crop, there are a lot of them here in my yard here in Calofornia, is stellar!