Camelot

Camelot is a realm famed for containing the legendary sword of Excalibur.

Before the Curse
When Prince Charming led Snow White to a fake version of Excalibur, he told her that it was forged by a mage called Merlin in the realm of Camelot. Later, when Snow discovers the sword is a fake, Rumplestiltskin tells her "everyone knows it's in Camelot", referring to the real Excalibur.