Useful links for this term:
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1. Leonardo da Vinci's top inventions:
https://www.youtube.com/watch?v=PwOlIGGDVjE

2. Sydney terrace houses
http://www.abc.net.au/news/image/4099698-16x9-940x529.jpg

3. Examples of New York skyscrapers:
https://i.kinja-img.com/gawker-media/image/upload/t_original/1208840420708284820.jpg

4. Secret codes
https://sites.google.com/site/codesforscouts/code-word

5. How to tie a reef or square knot
https://www.youtube.com/watch?v=cuNwp_Pi33s

​6. http://www.wikihow.com/Tie-a-Square-Knot

7. How to tie a bowline knot
https://www.youtube.com/watch?v=Q9NqGd7464U

​8. The snowy owls
https://www.youtube.com/watch?v=d2c-PHB18fU

9. History of the pen
https://www.youtube.com/watch?v=gnUbzg0PxsY

10. Position of the Galilean moons
http://www.shallowsky.com/jupiter/

11. How a ballpoint pen is made
https://www.youtube.com/watch?v=uYme2M_YPu0

12. How to make rope from grass
https://www.youtube.com/watch?v=DljWyRQFrNc

13. The Story of Bottled Water
https://www.youtube.com/watch?v=Se12y9hSOM0

14. Human skeleton song
https://www.youtube.com/watch?v=aUHh8uMdBso