Cairns
From WikiRaider
Remark: This article describes the challenge-related objects called Cairns in Tomb Raider (2013). For information about the key found in The Lost Artefact, see Cairn Key.
Cairns are some kind of landmark found in the Shipwreck Beach location of Tomb Raider (2013). They are part of the Cairn Raider Challenge.
The cairns consist of a small pile of stones and a cross-like wooden feature on top with a helmet attached to it. They look a bit like a shallow grave.