Global Garden (stylized in all caps) is a manga by Saki Hiwatari, who is best known as the creator of Please Save My Earth.

The series was published in Hakusensha's Hana to Yume which comes out bi-weekly in Japan.

Einstein is living in regret of his discovery of mass-energy equivalence (E = mc²), believing it led to the construction of the atomic bomb.

They tell him that ever since the atomic bombing of Hiroshima and Nagasaki, Yggdrasil, the tree of life, is dying.

Ruika is pretending to be her young brother Masato, who died in an airplane crash, to keep her mother from grieving.