Firefighters try to extinguish a fire in the Kalyvia area some 30 kilometers (18 miles) south of Athens, Monday, July 31, 2017. Dozens of firefighters, assisted by five water-dropping helicopters, are battling a large brush fire south of Athens, but Greek authorities say no inhabited areas are in immediate danger. (AP Photo/Thanassis Stavrakis)

A local resident tries to extinguish a fire in the Kalyvia area some 30 kilometers (18 miles) south of Athens, Monday, July 31, 2017. Dozens of firefighters, assisted by five water-dropping helicopters, are battling a large brush fire south of Athens, but Greek authorities say no inhabited areas are in immediate danger. (AP Photo/Thanassis Stavrakis)

An helicopter drops water over a fire in the Kalyvia area some 30 kilometers (18 miles) south of Athens, Monday, July 31, 2017. Dozens of firefighters, assisted by five water-dropping helicopters, are battling a large brush fire south of Athens, but Greek authorities say no inhabited areas are in immediate danger. (AP Photo/Thanassis Stavrakis)

Firefighters try to extinguish a fire in the Kalyvia area some 30 kilometers (18 miles) south of Athens, Monday, July 31, 2017. Dozens of firefighters, assisted by five water-dropping helicopters are battling a large brush fire south of Athens, but Greek authorities say no inhabited areas are in immediate danger. (AP Photo/Thanassis Stavrakis)