Mykonos

Schools on Santorini - and other neighbouring islands including Anafi, Paros, Naxos and Mykonos - will remain closed until Friday, when authorities will make a decision about when they can re-open.

Over the past month, Efron had been travelling around Europe and was spotted in St Tropez, Mykonos and Paris.

But critics say the development has spiraled out of control in some areas, particularly on islands like Mykonos and Paros, where large-scale hotel complexes have mushroomed in recent years.

Mr. Spilanis, a native of Serifos, was one of several experts who addressed a November conference on Mykonos about how tourism has “radically changed” the Cyclades.

It was in Mykonos, their next stop, when plans hit a snag: The indoor court they’d booked for the day was no longer available, and similar options were slim on short notice.