Sparta

Sparta was a prominent city-state in ancient Greece, situated on the banks of the Eurotas River in Laconia, in south-eastern Peloponnese.

The Blood of Olympus
The Seven stop in Sparta to retrieve an ingredient needed for the physician's cure: the chained god's heartbeat. Piper McLean and Annabeth Chase descend into the Temple of Fear to find the statue of Ares, where the giant Mimas is awaiting them. During the fight, Piper releases the makhai (the "chained god's heartbeat") from the statue. Through help from Phobos and Deimos, she and Annabeth manage to defeat Mimas and escape the crumbling temple.