Since mid-July wildfires have torn through France, Spain, and Portugal forcing more than 300,000 people to evacuate their homes.

France has seen its worst fires in two decades, while officials in the Spanish capital Madrid say they are the worst the region has ever experienced.

President Emmanuel Macron, visiting the fire-ravaged area in the Gironde region, called the "completely unprecedented" wildfire the "toughest since World War Two".

It follows a sweltering summer of heatwaves across Europe. Late July saw another sharp rise in temperatures, with peaks of 41-42C expected in France.

Wildfires in the regions outside Madrid have burned about 254 sq miles (660 sq km) since 1 July, authorities estimate – an area larger than the city itself.

In France, the worst affected area is Gironde, around the city of Bordeaux, where more than 200,000 people have been forced from their homes.

The blaze spread rapidly, tearing through forests and fields in France's famous wine region, and burning more than 162 sq miles (420 sq km) in less than four days – an area roughly four times the size of Paris.

At its peak, the wildfire came now just nine miles (15km) to the south of Bordeaux, although the city was never under threat.

But the fires threatened a number of sensitive military and industrial sites in the area, including facilities that work on French ballistic missiles, rocket motors, and the processing of hazardous chemicals.

The fires have become so extreme they have created their own giant fire thunderstorm.

A rare weather event, storms like these are formed when heat from the wildfires makes the air above the fire rise rapidly, carrying smoke, ash and water vapour high into the atmosphere.

As the air rises, it cools, and the water vapour condenses into a cloud. If the fire is powerful enough and the atmosphere is unstable, that cloud can grow into a cumulonimbus – the same type of cloud associated with thunderstorms.

If these clouds then become large enough, they can produce their own lightning, which can then start new fires. They can also occasionally bring hail and rain.

These extreme and unpredictable conditions make the fires all the more difficult to stop.

To combat them, French firefighters have been using planes loaded with fire retardant, as well as planes like the Canadair, which can scoop 6,000 litres of water from lakes or the sea in 12 seconds and drop it directly on the fires.

On dangerous days, loaded aircraft patrol high-risk areas before any fires have been reported, so they can drop within minutes of a sighting. Planes often fly in a continuous shuttle while retardant is laid along the edges of the fire and ground crews attack the flames directly.

In Gironde, about 2,500 firefighters, 1,500 military personnel, and 1,200 police officers and gendarmes have been involved in tackling the blaze.

Four French firefighters died tackling the blazes, officials said.

But even with these numbers, Gironde official Jean Luc Gleyze told the BBC that authorities don't have enough people to combat the fires.

"We don't have enough people and enough trucks and even I think France don't have enough," he said.

Around the town of Lacanau, bulldozers, diggers and mechanical shovels have been used to carve a firebreak that is 100m (328ft) wide at points, according to French media.

A firebreak is a stretch of land that has been stripped of all vegetation to stop the fire from spreading – removing any potential fuel before the fire has a chance to reach it.

Spanish teams have been using many of the same techniques to tackle their wildfires, which are on course to become the worst the country has seen in two decades.

Francisco Martin, a government delegate in Madrid, described one of the fires as "undoubtedly the largest fire in the history of the Madrid region".

This summer's fires have been aided by the hotter, drier conditions caused by climate change, which allow fires to spread faster and burn more fiercely.

"The climate emergency is worsening year after year, and we are required to be united to fight against fire, as well as in prevention and reconstruction," Prime Minister Pedro Sánchez said.

Appealing to his country's regional governments, Sánchez added: "Climate denial is the worst fuel for the fight against the climate emergency."

Additional reporting by Elizabeth Rizzini and Helen Willetts. Visual Journalism by Pilar Tomas, Camilla Costa and Kate Gaynor.