https://www.nps.gov/jeff/index.htm
https://en.wikipedia.org/wiki/Gateway_Arch_National_Park
https://www.nationalparks.org/explore-parks/gateway-arch-national-park
Catenary Arches
https://en.wikipedia.org/wiki/Catenary_arch
https://kids.kiddle.co/Catenary
https://kids.kiddle.co/Gateway_Arch_National_Park
FREDERIC REMINGTON
Statue of Liberty Prezi- https://prezi.com/wtt1zhoi1maq/statue-of-liberty/
Facts about the Statue of Liberty- http://www.american-historama.org/1881-1913-maturation-era/statue-of-liberty-facts-kids.htm
More facts and Symbolism- https://kidzfeed.com/statue-of-liberty-facts-for-kids/#13_Statue_of_Liberty_Symbolism
National Geographic Kids- https://kids.nationalgeographic.com/history/article/statue-of-liberty
Skyscraper Research Page- http://skyscraperpage.com/diagrams/?searchID=200
Skyscrapers Research Page (Top 100)- https://www.skyscrapercenter.com/buildings
https://en.wikipedia.org/wiki/Hoover_Dam
https://www.usbr.gov/lc/hooverdam/
http://www.pbs.org/wgbh/buildingbig/wonder/structure/hoover.html
http://www.history.com/topics/hoover-dam#
http://www.waterencyclopedia.com/Ge-Hy/Hoover-Dam.html
https://sites.psu.edu/charlottekruse/2014/04/28/the-hoover-dam-and-its-importance/
MOUNT RUSHMORE
https://www.history.com/topics/us-presidents/mount-rushmore
https://www.nps.gov/moru/index.htm
Norman Rockwel