A huge blanket of cobwebs has cloaked a lagoon-side area in the western Greek town of Aitoliko.
The webs cover palm trees and plants in an area at least 300 metres long, the Daily Hellas reports.
Locals said the sudden rise in spiders had come with the arrival of mosquitoes in the town.
The spiders are likely to be from the genus Tetragnatha, commonly referred to as stretch spiders due to their elongated bodies.
The genus covers hundreds of species which are found all over the world, although most occur in the tropics and subtropics.
Some of the species are known to live near lakes or on river banks.
Molecular biologist Maria Chatzaki told Greek news website Newsit.gr: “These spiders are not dangerous for humans and will not cause any damage to the area’s flora.
“The spiders will have their party and will soon die.”
Ms Chatzaki has said the phenomenon can occur every couple of years.
She said the reason for the expanse of webs is a combination of timing and opportunism.
“When animal finds abundant food, high temperatures and sufficient humidity, it has the ideal conditions to be able to make larger population,” she added.
“This phenomenon has arisen from a population explosion of this spider.”