Final Fantasy X/Secrets and Sidequest/Secret World Map Locations

Baaj Temple

 * Location of Lulu's legendary Weapon, the Onion Knight.
 * Location of Anima, a hidden, powerful Aeon.

Sanubia Desert

 * Location of Tidus's Ascalon:
 * Has the Double AP ability.

Besaid Falls

 * Location of Kimahri's Dragoon Lance.

Mi'ihen Ruins

 * Location of Rikku's Sonar.

Battle Site

 * Location of Lulu's Phantom Bangle
 * Absorbs three types of elemental attacks.

Omega Ruins

 * Location of Ultima Weapon and Omega Weapon, two of the hardest fiends in the game.
 * Location of:
 * Al Bhed Primer vol. XXVI
 * 1x Teleport Sphere
 * 1x Magic Sphere
 * 1x Friend Sphere