It's not former Vice President Joe Biden's first time on the presidential train. But seeing as he's safely boarded — albeit a bit late — for 2020, let's take a look back at his past journeys.

Biden's first bid was for the 1988 presidential race and, in no surprise given his Amtrak obsession, he revealed it in a June 1987 speech in Wilmington, Delaware's train station.

Yet Biden failed to keep his run on the rails, and hopped out of the contenders' car just a few months later.

As promised in that 1988 speech, there were "other presidential campaigns," namely 2008's. Biden formally revealed his run in a Jan. 31, 2007 Meet the Press appearance, and followed it up with a video on his website.

Biden's withdrawal from the race didn't come until nearly a year later after rolling into fifth place in the Iowa caucus, and he made that choice in a small speech to supporters and staffers. Of course, Biden still ended up in the White House, becoming former President Barack Obama's running mate at this Aug. 23, 2008 event in Illinois.

Compare these past announcements to Biden's 2020 video here. Kathryn Krawczyk

The third time was a charm for biologists trying to successfully transfer embryos from one cheetah to another.

Cheetahs are endangered, and there are only around 7,000 in the wild. It's difficult for cheetahs to reproduce after age eight, but researchers determined that genetically, a 9-year-old female cheetah at the Columbus Zoo named Kibibi was a good match for a 3-year-old male named Slash living at the Fossil Rim Wildlife Center in Texas.

The Columbus Zoo, the Smithsonian's National Zoo and Conservation Biology Institute, and Fossil Rim Wildlife Center worked together to devise a plan to have the pair somehow reproduce. In November, Kibibi received hormone injections to stimulate follicle development, and had several eggs extracted and fertilized with sperm from Slash, which arrived in Columbus frozen. These embryos were implanted in a 3-year-old cheetah named Izzy, and an ultrasound in December showed she was pregnant with two fetuses. This was the third time they attempted the process, and the first time it worked.

Izzy gave birth on Feb. 19 to a male weighing 480 grams and a female weighing 350 grams. She is providing "great care" to the cubs, the Columbus Zoo told ABC News. The cubs don't have names yet, and won't be on display for several months. This is a "big win for the cheetah," Jason Ahistus of the Fossil Rim Wildlife Center said in a statement. "It really opens the door to many new opportunities that can help the global cheetah population." Catherine Garcia

Tokyo Olympics organizers are downplaying comments made by a member of the International Olympic Committee who said the coronavirus could cancel the games.

Richard Pound, a member of the IOC since 1978 and its former vice president, told The Associated Press that organizers have a three-month window to decide whether to hold the games, which are scheduled to start on July 24. Pound, who noted he was not speaking on behalf of the IOC, said, "In and around that time, I'd say folks are going to have to ask, 'Is this under sufficient control that we can be confident about going to Tokyo or no?'"

Yoshihide Suga, a Japanese government spokesman, said on Wednesday that Pound's opinion is not shared by the IOC, and organizers are "proceeding with preparations toward the games as scheduled." Catherine Garcia

When you land a new job you're not quite qualified for, you can pick top aides who will help you learn the ropes and get a running start — or you can hire someone with even less experience, thus making you the most qualified person in the room. That latter route seems to be the one taken by Johnny McEntee, President Trump's former body man and new director of the powerful Presidential Personnel Office.

Trump recently hired McEntee, a 29-year-old loyalist with no real personnel management experience, to oversee his post-impeachment effort to purge the executive branch of anyone not loyal to Trump. And McEntee promptly hired James Bacon, a 23-year-old college senior, as one of his right-hand men, Politico reported Tuesday. Bacon does have some experience, despite still pursuing his bachelor's degree at George Washington University: He briefly worked in the Transportation Department's policy arm, as a White House liaison to the Department of Housing and Urban Development, and on Trump's campaign.

McEntee replaced Sean Doocey, and Bacon is filling the lead paperwork directorship previously filled by Katie Bullock, who is in her 70s and worked in the PPO for all Republican administrations back to Ronald Reagan's White House, Politico reports.

Last Thursday, Politico and Axios report, McEntee called all the White House Cabinet department liaisons to a meeting at which he asked them to find Trump appointees who may be insufficiently loyal to Trump — officials Trump calls "bad people" and "Deep State," Axios notes. Trump acknowledged Tuesday that his White House has lists of government officials he wants to replace with trusted pro-Trump loyalists, telling reporters in New Delhi he "doesn't think it's a big problem" and he wants "people who are good for the country, loyal to the country."

Last week, Axios reported that the "Never Trump/pro-Trump" lists are being compiled by a network of conservative activists led by Ginni Thomas, the wife of Supreme Court Justice Clarence Thomas. James Bacon clearly mad the "pro-Trump" list. Peter Weber

Rep. Alexandria Ocasio-Cortez (D-N.Y.) watched Tuesday night's Democratic debate, and one thing stood out to her.

"Not a single climate change question," she tweeted. "Horrifying." One of the participants, Sen. Bernie Sanders (I-Vt.), agreed, responding, "A disgrace." The Democratic candidates don't shy away from talking about climate change on the campaign trail; billionaire investor and environmentalist Tom Steyer told voters in South Carolina on Tuesday that climate change is his "No. 1 priority," and if elected, he will declare a climate emergency on his first day in office.

Poll after poll has shown that climate change is a key issue for voters; last week, the Pew Research Center released a survey showing that for the first time in two decades, a majority of Americans believe that tackling climate change should be a main priority for the president and Congress.

Another poll released last week by the nonpartisan nonprofit Climate Nexus found that for Democrats, climate change is one of the two most important issues facing the country right now. "This is the first time in American political history where climate change is not just a top-tier issue, it is the top-tier issue," Anthony Leiserowitz, a senior research scientist at Yale who helped conduct the poll, told The Atlantic. Catherine Garcia

In her response to why she would make a better president than Democratic frontrunner Sen. Bernie Sanders (I-Vt.) during Tuesday night's debate in South Carolina, Sen. Elizabeth Warren (D-Mass.) compared their plans to expand Medicare-style health care to all Americans. Sanders let his body do the disagreeing, and if this whole president thing doesn't work out, his face has enough expressiveness to anchor, say, an HBO show about a curmudgeonly old man who frequently throws up his hands at the world.

Here's Warren's full answer on why plans and legislative strategy matter, with her face included. Peter Weber

A 23-year-old American soldier based in South Korea has tested positive for the new coronavirus COVID-19, the U.S. military announced Tuesday.

The soldier is stationed at Camp Carroll in Waegwan, and is the first U.S. service member to come down with the virus. He is under quarantine at his home, which is off base.

There are 1,146 confirmed cases of COVID-19 in South Korea, with more than half of the patients living in the city of Daegu. The soldier visited a military base in Daegu on Friday, and then returned to Camp Carroll. There are 28,500 U.S. soldiers stationed in South Korea, and the military said health professionals are "actively conducting contact tracing to determine whether any others may have been exposed." Troops have been told to avoid nonessential meetings and stay on base, The New York Times reports. Catherine Garcia