Border

https://en.wikipedia.org/wiki/Border
https://en.wikipedia.org/wiki/List_of_transcontinental_countries

Photos
http://www.viralnova.com/international-borders/

Line
http://www.borderlineups.com/

Inc
http://www.bordersystemsinc.com/
http://bordermerchantsystems.co.uk/
https://www.border-systems.com/

Floss
http://mentalfloss.com/article/29086/its-complicated-5-puzzling-international-borders

Site
http://www.boundaries.com/

Slides
http://www.slideshare.net/search/slideshow?searchfrom=header&q=boundry

Tube
https://www.youtube.com/results?q=nation+boundary