How we verify

1. Every sentence in a script is tied to a stored excerpt from Wikipedia or from a reference that the Wikipedia article cites. A claim without a supporting excerpt is removed before the video is made.
2. Dates and years must match the source exactly. Rounded figures are said as "about", "nearly" or "over".
3. When the primary reference (an archive, agency or museum page) can be fetched, we prefer it over the Wikipedia summary.
4. Text from Wikipedia is used under CC BY-SA 4.0; each video's description names the articles used.

Image sources

• U.S. National Archives (NARA) — https://www.archives.gov/
• NASA Image and Video Library — https://images.nasa.gov/
• Library of Congress — https://www.loc.gov/pictures/
• Wikimedia Commons (public domain / CC0 only) — https://commons.wikimedia.org/
• Openverse (public domain / CC0 only) — https://openverse.org/
• Pixabay (Pixabay Content License) — https://pixabay.com/service/license-summary/