AMNA NAWAZ: History buffs heading to Greece are mostly drawn to the country's wealth of classical temples and amphitheaters.

But now the Culture Ministry has opened a stunning restored palace from the Byzantine era in the 1300s.

Greeks claim the UNESCO World Heritage Site is a model of bringing ancient treasures back to life.

From Mystras in Southern Greece, special correspondent Malcolm Brabant reports.

MALCOLM BRABANT: Situated in the Taygetus Mountains high above ancient Sparta lies the ruined walled city of Mystras.

Its golden years were during the Middle Ages, when Mystras was a center for art and culture, and a key outpost of the Christian Byzantine Empire ruled from what is now Istanbul.

There are two ways to see this ancient treasure.

One is by going uphill, the other downhill.

There are 900 steps between, and the gradient is really steep.

So I think we will be going downhill.

For decades, the palace at the heart of the complex has been closed to the public.

But now, after renovation work lasting 40 years, this UNESCO World Heritage Site is open for all to see.

DIMITRIS VLACHAKOS, Tour Guide: It's something unbelievable.

And, of course, when we first entered, because even myself could not enter the palace earlier, it was something amazing, something taking you back to another world, to "Game of Thrones" or "Lord of the Rings" or something, as you're going to find out.

It's just amazing, and the work that they did is also great.

MALCOLM BRABANT: Dimitris Vlachakos has been a tour guide for 12 years and is an expert on this, the only remaining Byzantine palace in Greece.

DIMITRIS VLACHAKOS: The Byzantine Empire actually was the continuation of the Roman Empire to the east and became a Greek Roman Christian empire.

So when everything was collapsed in the western part of the Roman Empire, here, they were flourishing.

MALCOLM BRABANT: One of the priorities of the Greek authorities here has been to try to future-proof this side against the dangers of climate change, in particular wildfires.

And that's because the Greeks had a really narrow escape about 20 years ago, when a terrible wildfire got to the perimeter of ancient Olympia, where the Olympics started.

And it was just by pure luck and skill of the firefighters that they managed to stop it before it got inside.

Surrounded by forests, Mystras is a potential tinderbox.

DIMITRIS VLACHAKOS: This area is very similar to California, the wildfires, the earthquakes, the flora, and such other issues, the temperatures, of course.

So we have a big issue and a fear, a constant fear of a possible wildfire to break out.

MALCOLM BRABANT: And so the archaeological site has been kitted out with water tanks and the latest fire suppressant systems, which pleased Prime Minister Kyriakos Mitsotakis.

KYRIAKOS MITSOTAKIS, Greek Prime Minister (through translator): How can we talk about preserving our cultural identity if we do not protect it from the modern threats of the climate crisis?

Something that sits at the center of our priorities is the Ministry of Culture.

MALCOLM BRABANT: At the heart of the renovations is the Palace of the Despots.

In the Byzantine language, the word despot meant a prince, not a tyrant.

KYRIAKOS MITSOTAKIS (through translator): I also want to speak about the future.

When we talk about the future, our minds automatically go to technology.

All of our archaeological sites now, all of our monuments are incorporating technology so as to enrich the visitor experience and enable us to create personalized roots.

MALCOLM BRABANT: The palace transports visitors back in time by projecting ghostly images onto the stone walls.

A lady in waiting combs her mistress' hair, while a page is chastised by a cook in the kitchen.

Overseeing Greece's heritage is Culture Minister Lina Mendoni.

LINA MENDONI, Greek Culture Minister (through translator): Cultural heritage plays a crucial role both for collective self-awareness and for sustainable development and social cohesion.

With this strategic concept, we have been implementing in the last seven years the largest and most comprehensive investment policy in culture that the country has ever known.

MALCOLM BRABANT: Avatars of minstrels in the throne room provide a soundtrack as a Byzantine prince returns to the palace, to the acclamation of his subjects.

LINA MENDONI (through translator): It's proven in practice that when there's a plan, consistency, cooperation, and faith in the power of culture, we can give back to society with a substantial historical, cultural and developmental footprint.

MALCOLM BRABANT: As part of that promise, Greece has launched an initiative to protect 19 ancient monuments at high risk from climate change.

They include the Knossos in Crete, which is getting a fire suppression network and lightning protection system, because ever more powerful heat waves help to generate more wildfires.

Christos Zerefos heads the Academy of Athens Climatology Research Center.

CHRISTOS ZEREFOS, Research Center for Atmospheric Physics and Climatology, Academy of Athens: People in the past, they would say, OK, it's only a heat wave, it will pass in a few days.

Unfortunately, we see that the period of instability in weather becomes prolonged and becomes longer.

MALCOLM BRABANT: Scientists are also monitoring coastal erosion and rising sea levels around the island of Delos, where, according to Greek mythology, the sun god Apollo was born.

CHRISTOS ZEREFOS: We need to know the rate of deterioration and the extent of changes in the quality of the sea, like the pH of the waters.

The heat wave is maintained by the increase of the sea surface temperatures also, which follow the heating of the atmosphere by the greenhouse gases.

MALCOLM BRABANT: Visitors to Mystras cannot fail to feel the weight of history.

Protecting such irreplaceable treasures is not just a Greek responsibility.

According to UNESCO's abiding principles, it is the duty of all humanity.

For the "PBS News Hour," I'm Malcolm Brabant in Mystras, Southern Greece.