Made in Abyss: The Golden City of the Scorching Sun (1970)

After the events of Made in Abyss: Dawn of the Deep Soul, Riko, Reg, and Nanachi enter the weird bubble ship and descend through a deep ocean into a sunny land--the titular "land of the scorching sun." Nevermind the weirdness of a burning bright sun that fills a world under an entire sea...the land is filled with ruins and even more dangerous creatures than before.