The Death Caldera is a location in The Legend of Zelda: Breath of the Wild. It is located in the Death Mountain region of Hyrule in the province of Eldin. As its name implies it is the Caldera of Death Mountain that presumably formed as a result of Death Mountain's sudden increase volcanic activity that began shortly before the Great Calamity and has apparently remained active for at least a century though the caldera around the mountain is still filled with lava and magma indicating it hasn't fully collapsed or Death Mountain's volcanic activity keeps it from emptying completely.
Alternatively it formed relatively recently or Hyrulean volcanic processes differ from the real world which is suggested by Death Mountain's geological activity being effected as evil forces grow stronger as Death Mountain had been peaceful until shortly before the Great Calamity as signs of Ganon's imminent return increased.
As the caldera surrounding Death Mountain is filled with lava, the Goron's Bridge of Eldin is a drawbridge that allows them access to Death Mountain while at the same time it can be raised to cut off access when the mountain becomes too dangerous protecting travelers and Goron's alike as the Caldera's lava flows acts as a natural barrier enough to keep Divine Beast Vah Rudania trapped on the mountain.