Villages evacuated and ancient sites are under threat from fires ravaging Europe.

ATHENS — As southern Europe grapples with one of its worst heat waves in decades, deadly forest fires have engulfed stretches of the region, bringing tourism to a halt and forcing mass evacuations.

The raging fires saw beachside tourist destinations across the region abandoned as blazes forced residents from villages on the Greek islands and mainland, destroyed stretches of forest and homes in Turkey, and led to days of dramatic rescues in Italy.

The Greek government on Thursday increased the involvement of the military in tackling forest fires as dozens of blazes continued to burn across the country, fueled by a record-breaking heat wave that has battered the region.

At ancient Olympia, the birthplace of the Olympic Games, the local authorities and army personnel dug fire lines around the archaeological site to keep the flames at bay, as firefighters battled the blazes through the night.

“We will fight all day,” Michalis Chrysochoidis, the public order minister, said during a visit on Thursday to the ancient UNESCO World Heritage site.

While scientists have not yet had time to evaluate the connection between the current wave of extreme temperatures and global warming, it fits an overall trend that has seen climate change play a role in extreme weather in Europe. Research has shown that for major heat waves across Europe in recent summers, climate change has been a significant worsening factor.

A large fire that broke out north of Athens on Tuesday — and destroyed scores of homes and hundreds of acres of forest — was partially doused by Thursday, but firefighters remained on the scene as small fronts were rekindling, according to Vasilis Vathrakoyiannis, a fire service spokesman.

He said 120 fires were burning around the country on Thursday, the largest and most worrying on the island of Evia and ancient Olympia.

On Wednesday afternoon, the Greek coast guard evacuated dozens of people from the seaside village of Rovies on the island after a huge fire moved through a nearby pine forest.

Residents of at least 12 villages on that island were forced to abandon their homes on Wednesday, and the local authorities and the army dug fire lines to try to protect a monastery. The local church in the village of Kechries sounded its bells early Thursday morning to urge its residents to flee.

People in Athens were instructed to remain indoors on Thursday as a thick pall of smoke from the fire to the capital’s north hung over the city. A video posted by the National Observatory of Athens showed the extent of the devastation wreaked by that fire, with buildings and cars gutted by the flames. Swathes of forest were coated in a ghostly white, with once-green leaves reduced to a thick pile of ash.

Prime Minister Kyriakos Mitsotakis is scheduled on Thursday to visit the area of the Peloponnese peninsula that was ravaged in 2007 by fires that killed more than 60 people.

Earlier in the day, Mr. Mitsotakis met with defense and military officials and announced plans to boost military involvement in preparing for and tackling fires over the coming days as the ongoing drought and high temperatures will continue to increase the risk of fire.

Efthymis Lekkas, a professor of natural disaster management at the University of Athens, warned of “an enduring nightmare in August,” and urged the authorities to boost readiness for potential flooding after the destruction of large stretches of forest.