Ruins are objects on the map that units can move on, like villages. Unlike villages, though, they can occur on mountains or in oceans. Once a unit has moved into the ruin, it can be examined next turn and you will receive a reward. Below are all the possible rewards for a ruin to give you:
- Giant - Moves away your unit and creates a Giant, which can move and attack on the turn that you receive it. Alternatively, if you are playing as the Aquarion and the ruin is in the ocean, you will receive a Crab instead.
- Scrolls of Wisdom - Instantly researches a random available technology for you, for free.
- Population - Rewards you with 3 free population to your capital.
- Explorer - Self explanatory, spawns an explorer.
- Battleship (ocean only) - Similar to Giant, spawns a Warrior in a Battleship.
- Resources - you recieve 10 stars
Because of the variety of possible rewards, it can be risky to go for ruins and rely on them. Especially in early game there is the question whether to go for ruins or new villages. If the ruin is in a place that you can easily defend, it's usually smart to first expand your territory and upgrade your cities before you spend too much time with your units on ruins. If the ruin is between your enemy and you, try to capture it. You definitely don't want to take the risk that your enemy gets a giant close to your village for free.
- If a ruin spawns on an 1x1 island, and you get a message saying that the reward is a giant, then the unit examining the ruin will disappear and the giant will spawn. This disappearance counts as a death, so be careful when examining ruins on small islands.
- Ruins often are on the edges of the map
- There is a chance that whales are below ruins (ocean) and get visible once the ruin is gone