Hole

Hole is an Adventure Map feature that can be located on non-water tile. They can either be placed there by the map-maker or after a hero has digged the ground. Digging and holes have two purposes. Firstly, digging is basically the only way to acquire the grail artifact; the other one is to find a hero with the grail artifact. Secondly, tiles with holes in them cannot be disembarked with a boat. This makes digging holes next to the shoreline in order to prevent enemy heroes' invasions a strategic feature.