The US government has partially shut down — that is, all non-essential services have ceased, and over 800,000 workers have been furloughed.
While some of the effects won't be felt for weeks, other services — yes, even national parks — will be shuttered immediately.
Other services and government departments will run as normal, such as the postal service, military pay, Social Security, Medicare and, of course, the politicians will still get their paychecks.
President Barack Obama will also continue to get paid.
There are worries about how long the shutdown could last.
If it goes on for weeks, the US could default on its debts for not making the proper payments.
That's still a big "if," but the signs are troubling.
Here's the memo, which brings the most powerful country in the world to a grinding halt.
And here are some of the things that will be affected by the shutdown:
All federal parks and monuments were closed on Tuesday and will continue until the end of the shutdown. Planned a special vacation to Yosemite or wanted to see the Statue of Liberty? Not going to happen this time.
Of course, the dreaded TSA will still function, haranguing and harassing passengers boarding airplanes. And, yes, air traffic controllers will still make sure your flight arrives safely.
The Smithsonian Museum in Washington DC will be exceptionally quiet for the next few days, weeks or months.
Though the animals will still be cared for, the so-called "Panda cam" will be shut down, along with the zoo itself.
Yes, the exploration of the universe has been declared 'non-essential.' Luckily for the Americans on the International Space Station, there will still be a few people watching the computers on the ground.
The Centers for Disease Control and Prevention (CDC) will no longer be tracking the flu or outbreaks of diseases in States and counties for the moment. A good reminder to take a vitamin C.
Food for low-income mothers
The WIC program, a federal initiative that helps pregnant women and new mothers, is going on hiatus. State funds to fill in the gaps will last about one week.
Americans need to be extra careful where they buy their lettuce as the FDA is suspending most of its inspections. Meat will still be inspected thankfully.