Solar Tower

The Solar Tower is a supposedly hidden area in the Fourth Floor of Princess Peach's Castle that acts as a counterpart of the Lunar Tower. Much like the Lunar Tower, it is accessed by following a staircase similar to the one leading to the second floor.

The Solar Tower features a unique soundtrack, which can be listened to here.

Appearance
The area's structure is reported to be nearly identical to the Lunar Tower, being very tall, shaped like an octagon and it's floor being covered with grass and concrete. The roof of the tower is shaped like a cone and is textured like the castle's roof. It is currently not known what level can be accessed by looking at the ceiling of the tower, however it will depict an eclipsed sun before the level has been beaten, and change to an image of a normal sun after. This mirrors the function of the ceiling of the Lunar Tower, which has been reported to depict a red moon before beating Red Moon Monastery and change to an image of a normal crescent after. Much like Red Moon Monastery, the rumoured level accessed through the Solar Tower ceiling supposedly becomes inaccessible after the correlating tower's ceiling has changed. As mentioned before, the tower apparently contains a way to access an as of yet unknown course by looking directly at the eclipsed sun on the ceiling of the tower, which is supposedly dependent on the internal clock anomaly, as the course can supposedly only be accessed during sunrise-to-sunset. Before beating the supposed course, the screen is reported to have a dark tint in and around the castle while it's daytime and the sun will always appear as eclipsed. After the course in question has been completed however, the sun has been reported to revert to its normal state.

Eternal Sun statue
The area also contains a unique statue of a Sun in its center, the text on the plaque seems to differ from the texts on the Eternal Star and Eternal Moon statues. Much like with the previously mentioned texts, various theories about what the text on the Eternal Sun statue could mean have been proposed, however none of these can be verified because of it's low resolution. After multiple theorists proposed that the text of the Eternal Moon statue changes every time the player enters the area, the same phenomenon has been reported in regards to the Eternal Sun statue.

"Eternal Sun" statue plaque interpretations
There are reports claiming that the plaque sometimes depicts various kinds of encoded texts, ranging from caeser ciphers to cryptograms. These reports haven't followed up with their translations yet, so these claims should be taken with a grain of salt.

"Woven in the - Eternal Sun"

"We stem from - [Undecipherable letters] crib"

"The Light has changed - The form remained"

"Whatever Thought - Escapes [Undecipherable letters] lip"

"Blindfolded - No choice was made"

"No mediation - No more it (lt/id?)"

"No matter - Plane of shapes"

"[Undecipherable letters] - Powerless"

"[Undecipherable letters] with - Eternal Malice"

"I know the first - [Undecipherable letters] Numbers"