Only 20,000 daily visitors will be let into the Acropolis of Athens, Greece's most popular archaeological site, starting next month.
There will also be cap on how many visitors will be let in every hour.
Up until now, as many as 23,000 people a day have been squeezing into the monument complex, with mostly large groups visiting before noon.
Culture Minister Lina Mendoni said the controls are needed to prevent bottlenecks and overcrowding at the UNESCO World Heritage site.
'Excessive tourism' is a threat to the Acropolis
In a radio interview Mendoni said, “Obviously tourism is desirable for the country, for all of us. But we must work out how excessive tourism won't harm the monument.”
The new entry limits will be implemented on a trial basis from 4 September, and will come permanently into effect from 1 April 2024, the minister said.
There will be no time limit on visits although Mendoni said people who come with organised tours or from cruise ships, who account for about 50% of the daily visitor count, spend an average of 45 minutes at the site.
What time is the Acropolis open?
The site is open from 8am to 8pm Monday-Sunday.
Under the new rules, only a certain number of visitors will be allowed in every hour.
Half of the Acropolis' foot traffic currently arrives between 8 am and noon. Under the new system, 3,000 people will be granted access from 8-9 am, 2,000 during the next hour and the numbers will vary across the rest of the day.
“The measure will address the need to protect the monument, which is the main thing for us, as well as (improving) visitors' experience of the site,” Mendoni says.
Will other Greek sites follow suit?
Similar caps will be imposed for other popular archaeological sites, Mendoni says. The decision for the Acropolis followed consultations with tour and cruise operators, and was delayed due to Greece's June general election, she added.
More than 3 million people visited the site last year, according to Greece's statistical authority.
Acropolis responds to heatwave
Greek authorities closed access to the Acropolis and other ancient sites during midday hours last month at the height of a heat wave that also caused huge wildfires across the country.
They also installed awnings as sun protection for people lining up to see the Acropolis’ 5th century BC temples. Mendoni said those steps would be repeated, if necessary.