Group 1: Strange Structures

http://www.bbc.co.uk/guides/zg8q2hv#z82tpv4

https://www.natgeokids.com/uk/discover/history/general-history/stonehenge-facts/

https://www.forbes.com/sites/trevornace/2017/07/26/famous-easter-island-heads-have-hidden-bodies/#50ed9c37f804

https://theplanetd.com/easter-island/

Group 2: Mysterious Monsters

http://www.history.com/this-day-in-history/loch-ness-monster-sighted

http://www.pbs.org/wgbh/nova/ancient/legend-loch-ness.html

https://www.csicop.org/si/show/the_silver_lake_serpent_inflated_monster_or_inflated_tale

http://www.mywnynews.com/arcade_warsaw/news/local/article_e1a2e5b4-02bc-11e4-8765-0019bb2963f4.html

Group 3: Lost Cities & Souls

http://www.history.com/topics/atlantis

http://www.nationalgeographic.com/archaeology-and-history/archaeology/atlantis/

http://www.history.com/topics/bermuda-triangle

http://mocomi.com/bermuda-triangle-facts/

http://www.cnn.com/2017/07/06/us/amelia-earhart-mystery-theories/index.html

http://www.history.com/topics/amelia-earhart

http://news.nationalgeographic.com/2017/07/amelia-earhart-disappearance-theories-spd/

Group 4: Natural Wonders

http://news.nationalgeographic.com/news/2012/10/121031-singing-sand-dunes-physics-science-whistling/

https://www.mnn.com/earth-matters/climate-weather/blogs/everlasting-storm-has-1-million-lightning-strikes-a-year

(if the link doesn’t work, you may have to copy and paste the URL into the URL field)

Group 5: Out of This World

http://tvblogs.nationalgeographic.com/2010/06/01/space-jelly/

http://science.howstuffworks.com/science-vs-myth/unexplained-phenomena/star-jelly.htm

http://encyclopedia.kids.net.au/page/cr/Crop_circle

https://www.dogonews.com/2010/5/10/alien-crop-circles-are-back

http://www.npr.org/sections/krulwich/2010/05/28/126510251/aliens-found-in-ohio-the-wow-signal