The federal government shut down at 12:01 a.m. Saturday — meaning many of the government’s activities are about to grind to a halt.

Most federal employees will be furloughed. Smithsonian museums and the Library of Congress will shutter. Some activities will continue: Social Security checks will still go out, for example. But many of the government’s activities, from enrolling patients in clinical trials to processing passport applications, are on hold until the government reopens.

The Trump administration is encouraging agencies to remain open if they’re funded outside the annual appropriations process. So the Energy Department, for example, will remain open. In a contrast to the 2013, shutdown, so will national parks.

Federal employees deemed “essential” (or “non-excepted”) will still have to report to work, while the rest will be furloughed. No one gets paid until Congress passes a funding bill, and whether furloughed employees get paid is up to the government. (Members of the military will be paid unless the shutdown lasts past February 1, according to the Washington Post.)

Here’s what we know so far about how the shutdown will affect various agencies and services.

National Parks, Museums, Libraries, and Zoo

  • During the 2013 shutdown, all 401 national parks were closed, but this time parks with entrance fees will remain open, a senior administration official said on a call with reporters Friday night.
  • Smithsonian museums will be closed beginning Monday, but will be open over the weekend, as will the National Zoo. (In 2013, the zoo’s beloved panda cam was turned off.)
  • The Library of Congress will be closed beginning Saturday.

Health agencies