Where do whales go to die?

On the northern tip of New Zealand's South Island, there is a long bar of sand called Farewell Spit. The area is famous, but for an undesirable reason. It's a hotspot of whale strandings.In February 2015, 200 pilot whales became stuck on the shore. It was the biggest stranding in the area in over a decade, according to local conservation teams. Rescuers spent hours trying to re-float them but 100 died. Beaches like Farewell Spit are perhaps the most conspicuous places that whales can die.
To all intents and purposes, it seems as though the whales have committed suicide by swimming too close to the shore.
So are beaches like this the places where whales go to die – or are there other graveyards that we don't know about? It's a mystery that has been around since antiquity.