The most recent business plan puts the project $13 billion more expensive than previous estimates.
They now have permission to begin digging at a site in DC.
Elon Musk isn't the only one venturing below Earth's surface.
To begin, he's putting humans on Mars and computers in our brains.
A top tech adviser from the administration offered a clarification.
"Should be 2 miles long in three or four months and hopefully stretch the whole 405 [north to south] corridor from [Los Angeles International Airport] to the 101 in a year or so."
Musk clarified that nothing is official just yet.
Elon Musk answers the question, "Why are you boring?"
Over the weekend he snapped a photo of a Model S in the tunnel system.
From solar tiles with an infinity warranty to a company that is working to merge the human brain with machines, here’s what Elon has accomplished so far in 2017.
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