Intel or agitating? Hey there - From CNN, I'm David Rind with the Five Things you need to know for Saturday, March 18th.

We told you earlier this morning that former President Donald Trump says he expects to be arrested on Tuesday. I want to bring in CNN's Katelyn Polantz to get us up to speed because we've learned a little bit more since then.

Hi, David. Yeah, Donald Trump says he expects to be arrested on Tuesday, but this is Donald Trump speaking. It does not appear to be based on facts that his team has been told by the Manhattan district attorney's office that is doing this investigation. His spokesman this morning said that they have not received notification about when or what these charges might be. So what we can say now is that Trump is trying to send a political message to the Manhattan D.A., Alvin Bragg, and to his supporters who he's talking to, saying that they should protest, maybe come to his rallies. But at this time, the grand jury investigation is not done. And we are still waiting for word on whether those people in that grand jury would approve an indictment.

And we should say Trump has denied any wrongdoing in this case. But what are we actually talking about here? I know there are a lot of different Trump investigations swirling around. So I asked CNN's Senior Legal Analyst and former federal prosecutor Elie Honig to boil this one down for us.

Yet, David, so this case focuses on Donald Trump's payment of $130,000 in hush money to the adult film actress Stormy Daniels before the 2016 presidential election. Now, paying hush money is not illegal on its own, So it looks like this case focuses on whether Trump falsified business records to classify those payments improperly as legal fees and whether those payments constituted campaign contributions above the legal limits. Of course, if there is an indictment here, this will be the first time in American history that a president or former president has faced criminal charges.

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Protests continued today across France against the country's plan to raise the retirement age from 62 to 64. Things have gotten especially heated, literally. There have been fires in the days since the party of French President Emmanuel Macron used some legislative maneuvering to sidestep a vote in the country's lower house, where it does not have a majority. Mountains of garbage have been piling up in the streets since the protests began as strikes have affected trash pickup in Paris.

Russian President Vladimir Putin was in Crimea today for the nine year anniversary of its declared annexation. Remember, Russia annexed the Ukrainian territory after a 2014 referendum that was slammed by Ukraine and most of the world as illegitimate. His visit comes one day after Moscow dismissed the arrest warrant issued by the International Criminal Court for Putin and a top ally. Russia, like many other states, does not recognize the ICC's jurisdiction.

Coming up. It's like seaweed on steroids and it's coming for the U.S.

You may have heard about this giant blob of seaweed heading toward the U.S. And ever since I heard about it, I've been asking around CNN, basically wondering: uh, what? Luckily, our Florida based correspondent, Leyla Santiago was willing to fill me in.

So, David, I'm in Key West, and the reason I'm here is because one of the scientists I talked to told me there were already reports of sargassum washing up on the beaches. So what's Sargassum? Well, that's a type of seaweed that's part of this massive floating body out there in the tropical Atlantic. And it's making its way toward Florida's east coast. And it's massive. I mean, what's different about this is it is not a new type of seaweed. But when I looked at it with the scientists through satellite imaging, this is something that's five miles long, estimated right now to be about 6 million tons of seaweed, and that's not even pink. He told me that it could reach 20 million tons come summer. So obviously, that's a big concern for tourism because Florida depends on those beaches to attract tourists. And right now, there's no telling how much of this will hit Florida's east coast or when.

All right. It's all for us today. But if you want to join me tomorrow and go a little bit deeper, be sure to check out CNN One Thing. Just search for CNN One Thing wherever you get your podcasts. I'm David Rind. Talk to you later.