Spyglass

The Spyglass is a unique ability, featured in Age of Empires III.

It is available exlusively to Portuguese Explorers, and can be used to reveal parts of the map, not unlike Set players in Age of Mythology, who can use Vision to reveal concealed regions. This basically cuts through the fog of war, and allows the player to see unexplored territory, for a few seconds.

The Portuguese have an Industrial Age Home City Card named Bandeirantes, that ships two additional Explorers, but for balancing reasons all of them share the Spyglass ability, which means that if a single Explorer uses Spyglass, the rest of his peers will be unable to use it for a set amount of time (around a minute).