Greek authorities closed the Acropolis for Tuesday afternoon to protect workers and tourists during a four-day heat wave.
Temperatures were expected to reach up to 38 degrees Celsius (100 degrees Fahrenheit) in Athens.
The Greek Culture Ministry said the world-renowned site would be shut until 5:00 pm (1400 GMT) "for the safety of workers and visitors, owing to high temperatures."
The Labor Ministry also instructed outdoor workers in various parts of the country to stop work between midday and 5:00 p.m, with temperatures nationwide expected to peak at 43 degrees Celsius.
Greece grapples with heat wave
The 2,500-year-old Acropolis draws tens of thousands of visitors daily, totaling 4.5 million visitors last year.
But the ancient temple rests on a rock overlooking Athens, offering visitors very little shade.
Officials had been forced to order similar shutdowns of the Acropolis in recent years due to extreme weather .
The current heat wave is expected to last until Wednesday, with temperatures predicted to drop to a more tolerable 30 degrees by Thursday.
