Acknowledgements

A big thanks to all who published their amazing images to be used under these licenses:

• Half_dome_yosemite_nationalpark.JPG: HylgeriaKderivative work: Saibo (Δ), CC BY-SA 3.0, via Wikimedia Commons
• Uploaded by Meckimac, CC BY-SA 3.0, via Wikimedia Commons
• NASA, Public domain, via Wikimedia Commons
• Didier Descouens, CC BY-SA 4.0, via Wikimedia Commons
• Internet Archive Book Images, No restrictions, via Wikimedia Commons
• ermell, CC BY-SA 4.0, via Wikimedia Commons