Head to https://linode.com/scishow to get a $100 60-day credit on a new Linode account. Linode offers simple, affordable, and accessible Linux cloud solutions and services.

Our knowledge of specific technologies or techniques can sometimes be lost to time. And that can be because of changing economic conditions, or, sometimes, it's because the technology was so deadly that only a few were allowed to know it.

Hosted by: Michael Aranda

SciShow is on TikTok! Check us out at https://www.tiktok.com/@scishow
----------
Support SciShow by becoming a patron on Patreon: https://www.patreon.com/scishow
----------
Huge thanks go to the following Patreon supporters for helping us keep SciShow free for everyone forever:

Tomás Lagos González, Sam Lutfi. Bryan Cloer, Christoph Schwanke, Kevin Bealer, Jacob, Jason A Saslow, Nazara, Tom Mosner, Ash, Eric Jensen, Jeffrey Mckishen, Matt Curls, Alex Hackman, Christopher R Boucher, Piya Shedden, Jeremy Mysliwiec, charles george, Chris Peters, Adam Brainard, Dr. Melvin Sanicas, Harrison Mills, Silas Emrys, Alisa Sherbow

----------
Looking for SciShow elsewhere on the internet?
SciShow Tangents Podcast: https://scishow-tangents.simplecast.com/
Facebook: http://www.facebook.com/scishow
Twitter: http://www.twitter.com/scishow
Instagram: http://instagram.com/thescishow
#SciShow
----------
Sources:
https://www.britannica.com/technology/pozzolana
https://www.uh.edu/engines/epi2810.htm
https://unews.utah.edu/roman-concrete/
https://pubs.geoscienceworld.o....rg/msa/ammin/article
https://www.smithsonianmag.com..../history/the-secrets
https://www.britannica.com/tec....hnology/concrete-bui
https://www.britannica.com/top....ic/Pantheon-building

​​https://www.bbc.com/future/art....icle/20210316-the-le
https://uh.edu/engines/epi385.htm
https://library.oapen.org/bits....tream/handle/20.500.

https://www.britannica.com/technology/Greek-fire
https://www.jstor.org/stable/3....106585?origin=crossr
https://www.washingtonexaminer.....com/weekly-standard
https://www.thedrive.com/the-w....ar-zone/32867/fogban

https://www.ldeo.columbia.edu/....edu/eesj/gradpubs/Ge
https://brill.com/view/journal....s/east/17/1/article-
https://pubs.rsc.org/en/conten....t/articlehtml/2007/c

Images:
https://bit.ly/3wRfnlx
https://commons.wikimedia.org/....wiki/File:Vitruvius_
https://commons.wikimedia.org/....wiki/File:20_to_40mm
https://commons.wikimedia.org/....wiki/File:Puzzolane_
https://commons.wikimedia.org/....wiki/File:Pouzzolane
https://bit.ly/3tUXC2E
https://commons.wikimedia.org/wiki/File:AAC_13.jpg
https://commons.wikimedia.org/....wiki/File:Caesarea_C
https://commons.wikimedia.org/....wiki/File:Muslin_tra
https://commons.wikimedia.org/....wiki/File:Woman%27s_
https://commons.wikimedia.org/....wiki/File:Ancient_Mu
https://commons.wikimedia.org/....wiki/File:Renaldis_m
https://commons.wikimedia.org/....wiki/File:Victoria_M
https://commons.wikimedia.org/....wiki/File:DhakaCity1
https://commons.wikimedia.org/....wiki/File:Gossypium_
https://bit.ly/3IVa0nO
https://commons.wikimedia.org/....wiki/File:Muslin_men
https://commons.wikimedia.org/....wiki/File:Greekfire-
https://commons.wikimedia.org/....wiki/File:Hand-sipho
https://commons.wikimedia.org/....wiki/File:Arbalest_f
https://commons.wikimedia.org/....wiki/File:Trident_wa
https://www.flickr.com/photos/kevinpoh/3548617540
https://www.flickr.com/photos/....carolemage/129301370
https://commons.wikimedia.org/....wiki/File:Recreated_
https://commons.wikimedia.org/....wiki/File:Eastern_Ha
https://www.mdpi.com/2073-4352/9/5/273/htm
https://commons.wikimedia.org/....wiki/File:Tripod_cau
https://commons.wikimedia.org/....wiki/File:HKU_MAG_Fu
https://commons.wikimedia.org/....wiki/File:Egyptian_b
https://commons.wikimedia.org/....wiki/File:Western_Ha
https://commons.wikimedia.org/....wiki/File:British_Mu
https://commons.wikimedia.org/....wiki/File:Eastern_Ha
https://commons.wikimedia.org/....wiki/File:British_Mu