Taer Senadal is a stone fortress—but an unusual one.
Rather than being built to defend the region from
attack, this fortress is designed to be attacked. Taer
Senadal is defended by youths in the late stages of
their training, and it lives up to its name, loosely
translated as “fortress of whetstone.” Here, armies
take turns attacking the fortress, allowing the youths
to hone their skills as they defend it, while the army
practices assaulting fortifications.
Source: Chronicles of Eberron