Image in Answer 1 is from Wikimedia Commons https://commons.wikimedia.org/wiki/File:California_Palace_of_the_Legion… under the GNU Free Documentation License and Creative Commons Attribution-Share Alike 3.0 Unported license.
It is attributed to sailko
Image in Aswer 2 is from Wikimedia Commons https://commons.wikimedia.org/wiki/File:Pulgas_water_temple2.jpg under the Creative Commons Attribution-Share Alike 3.0 Unported license.
It is attributed to Leslieakf
The image in Answer 3 is from Wikimedia Commons https://commons.wikimedia.org/wiki/File:DeYoung_Museum.JPG 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.
It is attributed to Downtowngal
The image in Answer 4 is from Wikimedia Commons https://commons.wikimedia.org/wiki/File:San_Francisco_Palace_of_Fine_Ar… under Creative Commons CC0 1.0 Universal Public Domain Dedication license.
It is attributed to Author https://pixabay.com/en/users/cameralends-562673/