Oceanus

Oceanus is a small UNSC colony world notable for 90% of its surface being water. It was terraformed in 2168 for use as an agriculture world. Upon discovery of indigenous life and evidence of past alien civilization, however, the planet was declared a nature preserve. Strict laws were put in place to keep corporations from polluting the world, damaging the Oceanus farm and fishing industry. The planet became a haven for xenoarcheologists and followers of the religion Bela seeking spiritual enlightenment. In 2532, the planet was attacked by the Covenant Empire in the Battle of Oceanus, resulting the planet's eventual glassing.