Each year, as they have for centuries, hundreds of elephants descend on the shores of an ancient reservoir in Sri Lanka's north-central Minneriya National Park.<br /><br />The migration is called "The Gathering." Here, an adolescent elephant and its mother search for food after a muddy visit to what may be the world's largest pool party.
The Gathering -- Sri Lanka's elephant migration —
Each year, as they have for centuries, hundreds of elephants descend on the shores of an ancient reservoir in Sri Lanka's north-central Minneriya National Park.

The migration is called "The Gathering." Here, an adolescent elephant and its mother search for food after a muddy visit to what may be the world's largest pool party.
Kip Patrick/CNN
The increase in tourists to The Gathering -- and the jeeps needed to transport them -- is causing concern among conservationists, who worry the added traffic is impacting the health and behavior of the elephants.
Visitor impact —
The increase in tourists to The Gathering -- and the jeeps needed to transport them -- is causing concern among conservationists, who worry the added traffic is impacting the health and behavior of the elephants.
Kip Patrick/CNN
An adult female sprays herself with dirt and grass to help protect her skin and stay cool. Sri Lanka is home to an estimated 7,000 wild Asian elephants.
Staying cool —
An adult female sprays herself with dirt and grass to help protect her skin and stay cool. Sri Lanka is home to an estimated 7,000 wild Asian elephants.
Kip Patrick/CNN
The Gathering attracts some of the largest herds of elephants seen anywhere. Tourists in jeeps watch a group of more than 30 animals making their way toward Minneriya's reservoir.
Unique views —
The Gathering attracts some of the largest herds of elephants seen anywhere. Tourists in jeeps watch a group of more than 30 animals making their way toward Minneriya's reservoir.
Kip Patrick/cnn
A baby elephant reaches for its mother. Elephant moms typically don't stray far from their offspring, both for protection and in case they need to help sort out a quick meal.
Keeping close —
A baby elephant reaches for its mother. Elephant moms typically don't stray far from their offspring, both for protection and in case they need to help sort out a quick meal.
Kip Patrick/CNN