During your travels, you will most definitely come across a number of riddles that will ultimately lead you to a special treasure. One of those is the Lone Cove Riddle, as known as the III-Gotten Loot of Mad Oli:
"There's something on Lone Cove unseen, it's in a chest and has a sheen...
Find the grave of the beloved boar to the South West, a road to fortune with shovel's blase, 9 paces North-by-North West, a hole needs made..."
In order to solve this riddle, as it actually instructs you to do, you will actually need to head to Lone Cove. Once you read this location, head to the far southwestern corner of the island. In this section of the island, you should be able to find a grave surrounded by a number of boulders, the same that is also lit by a number candles. After finding it, what you actually will have to do to find the treasure chest is dig inside of the grave. But watch out, as things will get quite wobbly as you walk!