Jack and Laura Dangermond spent their honeymoon in a pup tent on a remote and spectacular stretch of southern Californian coast. They were students, idealistic and broke.

We both fell in love with that place – Jack Dangermond

Over the next 50 years the Dangermonds grew into billionaires, and all through those years they witnessed the unabating march of suburbia up and down the coast. Their old honeymoon haunt became part of a vast property owned by a hedge fund that develops coastal real estate.

We just thought, ‘Well, we just have to do this' – Laura Dangermond

So Jack and Laura spied a chance and swooped, shelling out $225 million to save for all time a 10,000 hectare tract of pristine coast and its hinterland of oak forests, hills, canyons and grasslands.

I didn't believe what I was hearing. This was a big piece of good news – Mike Bell from The Nature Conservancy, the environmental NGO which was handed the land, its biggest gift ever, by the Dangermonds

Jack and Laura Dangermond are private people who rarely talk to media. But they open up to Foreign Correspondent about how they pulled off this big green deal, and why. They hope their gift will inspire similar acts, big and small, and there is urgency to their message.

Time is running out. It's not dark yet but it's late in the day – and people are going to have to move to do this kind of thing in small ways and large ways all over the planet, really quickly – Jack Dangermond

Now they're challenging Australia's richest people to take a lead as well.

I want everybody in Australia getting this idea. I want those who really have large means to look at the amazing places in Australia before it's too late. And everybody else in Australia to plant one more tree, protect one more thing, to play at all levels - Jack Dangermond

The Dangermonds' conservation coup has come against the run of play, with the Trump administration seeking to roll back environmental safeguards and open up new territory for commercial development.

As North America correspondent Zoe Daniel discovers, Jack and Laura are no left-wing ideologues. Their environmental passion is founded on the hard data that drives their business. Founded nearly 50 years ago, their company ESRI leads the world in digital mapping, its software used by 350,000 organisations to predict flash floods, ease traffic snarls, help the homeless or plot the next Starbucks.

I like maps. They're a kind of language, the language of geography, the language of human activities, the language of understanding – Jack Dangermond

The fire came without warning, exploding in the twilight. It ripped through bushy hills and roared down on the little seaside haven of Mati, just outside Athens.

In Australia, we'd have a plan in place. There would be a text message saying, ‘the fire is at such and such. Get out.' - Stella Tzaninis, Greek-Australian part time Mati resident

But this was Greece. Burning cars choked narrow lanes. Illegally built houses blocked escape routes to the sea. Fumbling police sent traffic into the path of the inferno.

I can hear the people - in the cars, the old people, lots of old people. You can do nothing – Alex Tzaninis, who tried to help people to safety

Many who did make it to the beach died of burns or drowned as nearby tourist ferries kept plying their trade, emptying more cars into the fire zone.

By the time firefighters came, Mati was gone. By the time fireman Andreas Dimitriou came home, his fatally injured wife Margarita was alongside his dead baby son.

I don't know who to be angry with – angry with God? Angry with people? Angry with myself? – Andreas Dimitriou

Andreas' wife and son are part of a death toll that stands at 99 and may still go higher.

Greece is ringing with recriminations.

I cannot think of a single part that went right in this disaster. How is it possible that the system could leave these people so helpless? In Greece there is no culture of planning for big public emergencies - Costas Synolakis, crisis management expert

Was this simply a case of bungling and zero planning? Or something more? Greeks are arguing whether deep spending cuts from EU-imposed austerity made a bad situation truly catastrophic.

Firefighters say their budgets and wages have been cut; they even have to buy their own uniforms. Many fire trucks sit unrepaired and useless, while water-bombing planes are frequently grounded.

We've been paying with our own blood for a debt they created. It was not an accident. It is a crime demanding justice and punishment – former parliamentary Speaker Zoe Konstantopoulou

Reporter - Eric Campbell

Producer - Mark Corcoran
Camera - Greg Nelson
Editor - Garth Thomas
Executive Producer - Marianne Leitch

*This is the last episode of Foreign Correspondent's current season. The program will return in early January.