Today, President Trump held a national televised conference to tell the American citizens we are now in a 'National Emergence'.

It's not the first time a president has used such a declaration to deal with a public health crisis, but it is rare.  

Here's what a national emergency is:

"the life of the nation is threatened by war, invasion, general insurrection, disorder, natural disaster or other public emergency" and if the ordinary laws and government powers are not sufficient to restore peace and order.

Laws can be taken out or placed in for the health and safety of the American people.

He also announced that he would ban many foreign travelers from Europe for the next 30 days