Lunar Sea Spire

The "Lunar Sea Spire" was an abandoned temple that was once an oasis for Gems on Earth, according to Pearl. It is currently at the bottom of the sea since Steven failed to restore it in the episode "Cheeseburger Backpack".

About
The Lunar Sea Spire was a free-standing tower structure in the middle of the ocean. Each consecutive floor was slightly smaller than the one before and at the top was a shrine to the Moon Goddess. When the Moon Goddess Statue is returned to the pedestal, it repairs any damage to the structure. Gems used to gather at the Spire, but, in current times, the Spire has been abandoned. The Spire possessed an extreme gravitational pull that kept the waves from sinking it.

"Cheeseburger Backpack"
When the Crystal Gems visited the Spire with Steven, it was deteriorating and swarming with Crystal Shrimp. The Moon Goddess Statue was the one piece missing from the Spire that the Gems currently possess. It needed to be placed at the top of the spire before midnight, or the entirety of it would fall apart. Unfortunately, the temple sank beneath the waves because Steven forgot the statue at home.

"The Test"
Pearl accidentally told Steven that his mission to the Lunar Sea Spire was a test to assess his skills, stating that he had definitely passed with a grade of at least 75 percent. She also mentioned that the Spire should have been an even easier task, as it was in a much worse condition than the Gems had expected.

"It Could've Been Great"
Schematics for the Lunar sea Spire are seen on the Moon Base computer screen.

In Attack the Light

 * Attack the Light reveals the Lunar Sea Spire is still partly intact.
 * This location appears as the 4th world in the Steven Universe RPG: Attack the Light. It has 4 regular levels, 2 secret levels, a boss level and a gauntlet level, for a total of 8 levels.
 * The enemies are all blue and include a puffer-fish, starfish, angler-fish and jellyfish light monsters. The boss of this location is Blue Light, a whale.
 * The theme song is Sunken Sea Spire.

Trivia

 * When the Spire began to sink, the ocean moved in similarly to how Lapis Lazuli's water tower collapsed in "Ocean Gem".

Cultural References

 * Its design is reminiscent of the Tower of Babel, and the leaning tower of Pisa.