Scout towers are tall, sturdy structures constructed to guard the borders of many settlements. From these sites, the defenders of Lordaeron can spot enemy troops from high above, making it difficult for the orcs to launch surprise attacks. Their presence in the wildlands assures the swift deployment of our armies to meet any orc incursion. These towers may be outfitted with either deadly bolts that can pierce targets on land, sea and air, or with great cannon that while powerful, cannot attack threats from above.(WC2man 52)
These brick towers provide the first line of defense against enemy invasion. The arrows that fly from these bastions are renowned for their deadly accuracy.(WC3man 13)
Guard towers are a blood elf unit that are towers. They appeared in the Warcraft III The Frozen Throne human campaign to aid Kael'thas. It is built at the worker.
Statistics in Warcraft III (high elven)
21-29 piercing ranged damage
5 fortified armor
Statistics from Warcraft III (blood elven)
23-27 piercing ranged damage
8 heavy armor
In World of Warcraft
While human scout towers and orcish watch towers were plentiful, no true guard towers existed. In 0300, this has changed with the addition of such towers near places like the human settlement of Wintergarde Keep.