1) von Staudt (own work) [CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0)]; via Wikimedia Commons
2) by linz_ellinas (Flickr) [CC-BY-2.0 (www.creativecommons.org/licenses/by/2.0)] via Wikimedia Commons
3) by Daniel Wodischek (own work) [CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0) oder GFDL (www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons
4) by Roqqy (own work) [CC-BY-3.0 (www.creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
5) by kallerna (own work) [Public domain], via Wikimedia Commons
6) by Divulgação Petrobras / ABr [CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
*) Neue Jadewerft, Wilhelmshaven