Saihate no Tou, Iyahate no Shoujo-tachi

In a destroyed world, there is a comfy and gentle journey. The civilization is destroyed, the world has giant creatures dominating the land in place of the vanished humanity. The memories and recordings of the past human civilization are dissapearing. In this world, a pair of girls have the aim to keep walking to the giant tower that rises on the horizon.

(Source: Takeshobo, translated)