Flint spearhead, paleolithicum ca 50,000 BP combined with Mars north polar ice cap, 2011 AD (photo credit: ESA/DLR/FU Berlin G. Neukum)

Arrow head, archaic period ca 6,500 BP combined with Mars Murray Ridge 2013 AD (photo credit: NASA/JPL-Caltech/Univ. of Arizona)

Stone axe, paleolithicum ca 4,500 BC combined with Mars Promethei Planum, 2008 AD (photo credit: ESA/DLR/FU Berlin G. Neukum)

Nerita costata (photo credits: Llez & Islod Media World)