Here's the giant map the US uses to prep for inauguration

This is how the U.S. military plans for Inauguration Day: It uses a giant map.

The map is 40 feet by 60 feet and uses three-dimensional buildings. The same thing was used in 2012 and in 2008.

Security at Donald Trump's inauguration is expected to be challenging. Mainly because of the large amount of protests that are expected to take place.

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The D.C. National Guard is estimating around 800,000 people will attend the inauguration, although the numbers could be higher. President Obama's first inauguration drew a record-breaking 1.8 million people.

An estimated 13,000 service members will be supporting this year's inauguration.