Giant dump trucks haul raw oil sands in Alberta, Canada. Todd Korol/Reuters President Donald Trump on January 24 signed an executive order to revive and expedite two multibillion-dollar underground pipelines that would snake oil through US states to centers of the petroleum industry.

One is the contentious $3.8 billion Dakota Access pipeline, which would shuttle petroleum more than 1,100 miles, from North Dakota's Bakkan oil fields to holding tanks in Patoka, Illinois.

The other is the Keystone XL pipeline — a new segment of the existing Keystone Pipeline system, which begins in the Alberta, Canada, oil sands, also called tar sands (use of either term is controversial), and ends in Patoka as well as points in Texas along the Gulf of Mexico. The XL segment, which could cost its builders as much as $10 billion, is partially built and would move larger volumes of oil in less time by shortening the route and burying larger-diameter pipes.

Proponents of the pipeline say it will lessen dependence on foreign oil while creating jobs and growing domestic industry. But many Americans, and primarily Native Americans, are furious about Trump's latest executive order.

Barack Obama killed the Keystone XL pipeline in November 2015, saying it wouldn't have helped lower gas prices or create that many jobs. He also said the long-term contribution to climate change — possibly more than 22 billion metric tons of carbon pollution, according to Scientific American — wasn't worth the loss of America's global leadership on fighting emissions that exacerbate global warming.

"If we're going to prevent large parts of this Earth from becoming not only inhospitable but uninhabitable in our lifetimes, we're going to have to keep some fossil fuels in the ground," Obama said.

Trump's televised revival of Keystone XL didn't mention its steep environmental costs, including the 54,000 square miles (140,000 square kilometers) of pristine Alberta wilderness that may be industrialized to feed it.

"We're not saying the project is good or bad. We're just saying the scale and severity of what's happening in Alberta will make your spine tingle," Robert Johnson, a former Business Insider correspondent, wrote after flying over the Canadian oil sands in May 2012.

Keep scrolling to see an updated version of Johnson's photo essay, which shows Canadian oil mining — a process in which tar-laden sand is dug from the ground and the oil is separated through a lengthy and messy process.

This story has been updated to include details about in situ extraction, which is different from the mining method and makes up about half of Canada oil sands production.