The Treasury Department reported on Tuesday that for the first time, the national debt has soared above $22 trillion.

The national debt was at $19.95 trillion when President Trump took office. Over the last month, the national debt increased by $30 billion to $22.012 trillion, quickly rising due to the 2017 Republican tax bill and an increase in domestic and military spending. Experts say this could lead to an increase in interest rates, and make it more difficult for the government to cover programs.

Judd Gregg and Edward Rendell, co-chairman of the nonpartisan Campaign to Fix the Debt, told USA Today that the debt surpassing $22 trillion is "another sad reminder of the inexcusable tab our nation's leaders continue to run up and will leave for the next generation." Gregg and Rendell added that the "fiscal recklessness over the past few years has been shocking," and few people have been "willing to step up with a real plan." Catherine Garcia

Special Counsel Robert Mueller's investigators followed "several meandering paths" in their two-year investigation, "propelled by discoveries of unusual interactions between Trump associates and Russians," The Washington Post reported Sunday night. Mueller uncovered a lot in his 448-page final report, but his team was left with "some unanswered mysteries, a lot of dead ends and, ultimately, a conclusion that the contacts they found did not establish a criminal conspiracy," the Post says.

Mueller's team had to grapple with a legal dispute with Attorney General William Barr over whether a president can even be accused of crimes, plus President Trump and his son Donald Trump Jr. refused to be interviewed, and the witnesses they did have "were not ideal," the Post reports:

A few key players, prosecutors would contend, lied in interviews. Many were loyal to the president and echoed his rhetoric that Mueller's team was acting in bad faith. Some used encrypted applications with disappearing messages that could not be reviewed. Others were overseas, unreachable to American investigators. In some cases, their statements were only loosely tethered to the facts. [The Washington Post]

Ex-Trump campaign chairman Paul Manafort fits in the first three categories, and the "loosely tethered" description matches conspiracy theorist Jerome Corsi, the Post reports, citing an interview with Corsi's lawyer, David Gray. Corsi had offered "tantalizing leads" about Roger Stone and WikiLeaks, but his story was never quite straight and his leads always led to dead ends, the Post reports.

Trying to get actionable material out of Corsi, "it's their biggest nightmare," Gray told the Post. "The supposed best of the best were just frankly dumbfounded by the whole situation." Corsi was not charged, he added, because after six marathon interviews, "at the end of the day, they threw up their hands and said, 'We can't use any of this.'" Read more about the obstacles Mueller could't get over at The Washington Post. Peter Weber

John Oliver's main story on Sunday's Last Week Tonight focused on — what else? — Special Counsel Robert Mueller's report, which he framed as the latest and maybe last chapter of his "Stupid Watergate" series — "basically Watergate, but if Nixon had been kicked in the head by a billy goat, and also if that billy goat had been the White House chief of staff."

Once people actually read the 448-page redacted report released Thursday, "it became clear that there was a lot in it," Oliver said. "And some of the details in this report were incredible." The one he lingered on, with artistic license, was Trump reportedly saying Mueller's appointment marked "the end of my presidency, I'm f---ed" — except Oliver, of course, did not censor the F-word. Since "we clearly can't cover everything in the report tonight," he said, "I'd like to concentrate on two key factors that may have saved the president here": Incompetence and disobedience.

"When it comes to conspiracy, Trump's saving grace may have been that despite Russians wanting to help," his campaign and family displayed "often cartoonish levels of disorganization and incompetence," plus "ignorance of basic legal concepts," Oliver said. He said the report's findings that so many of the people in Trump's orbit just ignored his orders to potentially obstruct justice is "both reassuring and also terrifying," though worryingly, "lots of those people are gone now, and the newer figures seem very much on the same page as the president," notably Attorney General William Barr.

Barr's preemptive spin now "seems laughably and willfully misleading," Oliver said. "It's like Barr summarized the Twilight novels as: 'A girl in Florida goes to third base with a wookie.'" The parts of Mueller's report we can read may feel like a letdown, he said, but its imparted knowledge "can inform Congress going forward and, crucially, voters a year and a half from now." The clip is full of NSFW language. Watch below. Peter Weber

There are many reasons people who work in the White House are reluctant to take notes, and traditionally they center around protecting the president. But lots of people in President Trump's White House took notes for the opposite reason, report Peter Baker and Annie Karni at The New York Times: To protect themselves against "a mercurial, truth-bending chief executive who often asked them to do things that crossed ethical or even legal lines, then denied it later."

Some notes by Trump staffers have ended up as tell-all books, but Special Counsel Robert Mueller's report also drew from contemporaneous notes, shining new light on Trump's actions — and his strong aversion to note-taking, especially since he can no longer rely on nondisclosure agreements.

Mueller's team obtained notes or contemporaneous memos from former White House Counsel Don McGahn, his deputy Annie Donaldson, former White House Chiefs of Staff Reince Priebus and John Kelly, former Trump campaign chiefs Paul Manafort and Corey Lewandowski, adviser Stephen Miller, and other advisers, lawyers, and government officials. Some of them kept notes of alarming conversations with Trump in safes, according to Mueller's report.

We know Trump hated note-taking from McGahn's notes and Trump himself, who alleged in a Friday tweet that some "so-called 'notes' ... never existed until needed" and contained "total bullsh-t." Trump also publicly berated former National Security Adviser H.R. McMaster for taking copious amounts of notes, the Times reports.

W. Neil Eggleston, who served as a lawyer for President Bill Clinton and as president Barack Obama's White House counsel, told the Times he "didn't take notes when I worked with either president," but to protect the presidents, not make sure he wasn't "part of a criminal conspiracy," like Trump's aides. "To create records of information that was quite harmful to the president, that is really remarkable," he added. "And to do it and then stay on and continue to write them, is really something to me." Read more at The New York Times. Peter Weber

Every time Avery Fauth, her two sisters, and her parents visit North Topsail Beach in North Carolina, they scan the sand, hoping to spot an ancient megalodon shark tooth.

The family kept up their tradition while at the beach over spring break. As they walked along, Fauth, a middle school student from Raleigh, saw something that caught her eye. Intrigued, she went to the object, which was buried in the sand. "I uncovered it and it keeps coming, and it's this big tooth, and then I hold it up and I'm screaming for my mom," Fauth told WECT.

It was a megalodon shark tooth, and her father, who started searching for megalodon teeth 25 years ago and got his daughters hooked on the hunt, was stunned. "I was really shocked and excited for her that she found something that big," he said. The megalodon, the largest shark ever documented, went extinct millions of years ago, and Fauth's tooth could date back three million years. "They're really rare to find and they're some pretty big teeth and they're pretty cool," she said. The tooth will live in a "special box" inside Fauth's home. Catherine Garcia

After creating a replica of the Iron Throne from Game of Thrones, welding student Michael Hayes can tackle anything.

The Louisville, Kentucky, resident attends the Knight School of Welding. Ahead of his wedding, the Game of Thrones fan decided to make the ultimate gift for his soon-to-be wife: an Iron Throne. He enlisted some of his instructors to help him, and over the course of two months, they cut out 400 aluminum swords for the 200-pound throne.

It took nearly 110 hours to complete the throne, which became the centerpiece of Hayes' wedding. His new wife, Kacie, was impressed not only by the throne, but by how much work Hayes put into the project. "The show is one of the first things my wife and I bonded over," he told WLKY. "It's a really important thing for us." The Knight School of Welding funded the $7,000 project, and it's now renting the throne out to fans holding watch parties and Game of Thrones-related events. They're sitting on something special: Instructor Anthony Williams says the throne is even more authentic than the one used on the show, which is made of fiberglass. Catherine Garcia

Secretary of State Mike Pompeo is planning on telling allies Japan, South Korea, and Turkey on Monday that the United States will begin sanctioning them if they keep importing Iranian oil, three U.S. officials told The Associated Press on Sunday.

After the Trump administration pulled the U.S. from its 2015 nuclear deal with Iran, eight countries who received oil from Iran were granted sanctions waivers and told they needed to start looking for alternate energy sources. Greece, Taiwan, and Italy have all stopped importing oil from Iran, but Japan, South Korea, Turkey, China, and India have not, and the waivers expire on May 2. Turkey has been vocal about the fact that it needs Iranian oil to meet its energy needs, with senior officials urging the U.S. to reconsider, AP reports.

President Trump decided on Friday not to extend the waivers, as a way to pressure Iran, officials said. It's unclear if sanctions will start on May 3 if the countries do not immediately stop importing the oil. Catherine Garcia