ATHENS - The Athens Acropolis, Greece's most visited tourist site, was closed to the public during the hottest hours of Wednesday as the season's earliest-ever heatwave swept the country, prompting school closures and health warnings.
The UNESCO-listed archaeological site closed from midday to 5pm, with temperatures topping 43 degrees Celsius in central Greece.
Temperatures of up to 44 degrees Celsius are expected on Thursday as the phenomenon peaks, with up to 43 degrees forecast in the capital.
Meteorologists have noted this is the earliest heatwave -- which for Greece is temperatures exceeding 38 degrees Celsius for at least three days -- on record.
"This heatwave will go down in history," meteorologist Panos Giannopoulos said on state TV ERT.
"In the 20th century, we never had a heatwave before June 19. We have had several in the 21st century, but none before June 15," he said.
The climate crisis and civil protection ministry has warned of a very high risk of fires in the Attica region around Athens.
Schools stayed closed in several regions of the country on Wednesday and will do so again on Thursday, including in the capital, while the labour ministry has advised public-sector employees to work from home.
The ministry also ordered a pause from midday to 5pm for outdoor work including food delivery.
An air-conditioned hall has been opened at Syntagma metro station in central Athens to give people somewhere to shelter from the heat, the public transport authority said.
Greece's Red Cross said it had handed out some 12,000 bottles of water in the centre of the capital and at the Acropolis.
In Greece's second city Thessaloniki, teachers and pupils said annual school exams were held under difficult conditions.
A record number of almost four million visitors flocked to the Acropolis last year, with its popularity boosted in part due to tourists arriving on cruise ships calling in at the nearby port of Piraeus.