This is a file from the Wikimedia Commons and may be used by other projects. Information from its description page there is shown below. Commons is a freely licensed media file repository.
Summary
Description'Caldeira Grande' at 'Lagoa das Furnas', Azores, P.jpg
Deutsch: Die Caldeiras sind vulkanisch erhitzte Erdlöcher mit kochenden Schlamm oder Wasserdampf.
English: The caldeiras are volcanically heated holes in the ground with boiling mud or steam.
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.