The Littorina Sea, 7 500 - 7 000 years before present (5 500 - 5 000 BC). Shows post-glacial rebound and shore displacement of the Baltic Sea. Based on Ernman (2001).
<a href="//commons.wikimedia.org/wiki/User:Koyos" title="User:Koyos">Koyos</a>
Own work by uploader + Online map creation; data from Ernman (2001)