Temple of Seasons

Exclusively appearing in Oracle of Seasons, the Temple of Seasons was once located in the northwestern corner of Holodrum. In the game's opening, Onox submerged it into a molten underworld known as Subrosia in order to suppress the Season Oracle's power, then replaced it with his castle. Though some minor parts of the temple were destroyed in the process, all four Towers managed to stay intact.

Season Spirits
Each corner of the Temple has a tower with one of the Season Spirits inside; the Winter Tower holds the Winter Spirit, and the setup repeats for the Spring, Summer, and Autumn Towers. The Season Spirits are four fairy-like beings acting as the source of Seasons and perhaps even the oracle Din's power.

After Link travels to Subrosia to find the submerged Temple of Seasons, the spirits grant him the Rod of Seasons, which can be used to change the current season to any other season he has power over. Each newly-met spirit offers Link power over their season, explain what uses their respective season has, then beseech him to rescue Din. Link can't reach all four spirits immediately, as different towers of the temple require individual tools from various dungeons to gain access.

Oddly enough, there is a secret room in the back of the waterfall, that does absolutely nothing.