Delos is the island where Leto gave birth to the Greek gods Artemis and Apollo. The reason she had to give birth there is because
Hera put a curse on Leto forbidding her to give birth on any steadfast land. Delos was the only piece of land in the whole world that wasn't fastened down. Poseidon raised the island from the sea bed and held it in place for her. After Leto gave birth, she blessed the island and gave it pillars to hold it to the Earth. When the twins were born, the island was so happy that it covered itself in little yellow flowers. However, because the pillars Leto gave it anchored it to the world, it could no longer float around. Therefore, the flowers were nicknamed "the curse of Delos".
Reconstruction of the Temple of the Delians, sacred to Apollo