
Kos has been inhabited for roughly 10,000 years, and has for a significant
portion of that time been both an important center of commerce and a line of
defense. Its population in ancient times may have reached 100,000, but today it
is less than a third of that number. With whitewashed buildings including many
hotels, restaurants and a small number of nightclubs forming the famous Kos town
"barstreet", the town has a 14th century fortress erected in 1315 by The Knights
of Saint John of Rhodes at the entrance to its harbor.
The ancient physician Hippocrates is thought to have been born on Kos, and in
the center of the town is the Plane Tree of Hippocrates, a dream temple where
the physician is traditionally supposed to have taught. The limbs of the now
elderly tree are supported by scaffolding. The small city is also home to the
International Hippocratic Institute and the Hippocratic Museum dedicated to him.
Near the Institute are the ruins of Asklepieion, where Herodicus taught
Hippocrates medicine.