The image in the Explanation is from Wikimedia Commons under the Creative Commons Attribution-Share Alike 4.0 International license.
https://commons.wikimedia.org/wiki/File:Old_St._Mary%27s_Cathedral_(San….
_(1a).jpg){kind=link}
It is attributed to Chris06.
It is unmodified.
The first image in the Explanation is from Wikimedia Commons under Creative Commons Attribution-Share Alike 4.0 International license.
https://commons.wikimedia.org/wiki/File:San_Francisco_-_Old_Saint_Mary%…
It is attributed to Ramesh lalwani
It is unmodified.
The second image in the Explanation is from Wikimedia Commons under the GNU Free Documentation License, and Creative Commons Attribution-Share Alike 4.0 International, 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic licenses.
https://commons.wikimedia.org/wiki/File:Old_Saint_Mary%27s_Cathedral_ma…
It is attributed to BrokenSphere
It is unmodified.