If we were to journey to the center of the Earth, it would take a lot longer than you might expect. Here\'s how deep humans have dug underground.
Tech Insider tells you all you need to know about tech: gadgets, how-to\'s, gaming, science, digital culture, and more.
Subscribe to our channel and visit us at: http://www.businessinsider.com/sai
TI on Facebook: https://www.facebook.com/techinsider
TI on Instagram: https://www.instagram.com/tech_insider/
TI on Twitter: https://twitter.com/techinsider