By Karen Rosen | July 20, 2017, 3:14 p.m. (ET)

With Hungary known as the “land of waters,” Budapest is a fitting host for the 17th FINA World Championships. Diving, water polo, synchronized swimming and open water swimming are already underway with the marquee event – swimming – beginning Sunday at the Danube Arena on the east bank of the Danube River.

Download the Team USA app today for breaking news, Olympic and Paralympic team bios, videos and more.

Here are some burning questions facing Team USA in the swimming pool:


1. How many medals will Katie Ledecky win and will she break any world records?

The most dominant distance freestyle swimmer in the world could be busier in Budapest than she’s ever been in previous world or Olympic competition.  

Ledecky already has nine world gold medals – four from 2013 in Barcelona, Spain, and five from 2015 in Kazan, Russia. Two years ago, her medal total tied her for eighth among countries, although her five golds were exceeded by only two nations: the U.S. and Australia.

At the Olympic Games Rio 2016 Ledecky won three of the four freestyle events: the 200-, 400- and 800-meter. She won a fourth gold by swimming a leg on the 4x200-meter freestyle team and also won a silver -n the 4x100-meter freestyle.

In the women’s 1,500 – a standard event at worlds and recently announced as a new addition for the Olympic Games Tokyo 2020 – Ledecky is simply in a different pool than anyone else. Her top time this year is 25 seconds faster than her closest rival, teammate Leah Smith.

Ledecky, 20, could also show off her sprinting chops in Budapest if U.S. coaches select her to race on the 4x100 team.

There is almost a sigh of disappointment from the crowd when Ledecky doesn’t set a world record. She is the world-record holder in the 400, 800 and 1,500 and has frequently lowered her own records. In Kazan, she set world records in the 800 and 1,500 and a championships record in the 400.


2.  Who will be the breakout star on the men’s side without Michael Phelps or Ryan Lochte?

Either Phelps or Lochte competed at every worlds from 2001 to 2015 – a total of eight editions. Between them, they won 60 medals – 33 for Phelps (including 26 golds) and 27 for Lochte (with 18 golds).

Now Phelps is retired – though he can be seen on television Sunday after the swimming competition is over for the day in Budapest. As part of the annual “Shark Week,” Phelps is supposed to race against – you got it – a shark. The segment is titled “Great Gold vs. Great White.”

Lochte, meanwhile, was not allowed to compete at the U.S. national championships, the qualification meet for worlds, because he was still under suspension for the Rio gas station incident. That suspension ended earlier this month.

Look for Chase Kalisz to possibly inherit Phelps’ and Lochte’s mantles in the individual medleys.

In the 400 IM, Kalisz won the silver medal in 2013 and the bronze in 2015 as Japan’s Daiya Seto won gold both times.

Kalisz won the silver in Rio by swimming a personal best of 4 minutes, 6.75 seconds. Japan’s Kosuke Hagino won the gold with Seto taking the bronze.

The 200 IM is up for grabs, with Kalisz in the mix in that event as well.

Ryan Murphy won three gold medals in Rio – the 100 and 200 backstrokes and on the 4x100-medley team – with only Phelps winning more golden hardware among the men. However, Murphy will face stiff competition in the 100 back from teammate Matt Grevers, the 2012 Olympic gold medalist who did not make the squad in 2016. Grevers upset Murphy at this year’s nationals.

Grevers also medaled in the last two worlds, winning gold in 2013 and bronze in 2015.

Nathan Adrian, who is tied for fifth on the all-time U.S. men’s medal list with nine world championships medals, could make waves in the 50 and 100 freestyles. Caeleb Dressel will line up against him in both freestyle events, as well as swim the 50 and 100 butterflies in hopes of claiming his first world medal.


3. Can Team USA end its medal drought in the women’s 50-meter freestyle?

An American woman has not medaled in this event since Amy Van Dyken won the gold in 1998, meaning Team USA has come home empty-handed seven times in the last 20 years.

Simone Manuel won the silver medal in Rio behind Pernille Blume of Denmark. This season, Manuel has clocked 24.27 seconds to rank No. 3 on the world list behind Sarah Sjostrom of Sweden (23.83) and Blume (24.13).

Manuel, who tied Penny Okeksiak of Canada in the 100 free in Rio, will also be one of the women vying to be the first to go under 52 seconds. However, she was upset by Mallory Comerford in the 100 at nationals – despite swimming faster than she did at the 2016 U.S. Olympic Team Trials for Swimming.


4. Can Team USA get back on the podium in the men’s 4x100 freestyle?

The American history in this event is formidable. Team USA has won 11 of the 16 gold medals in this event, starting with a streak of eight golds from the inaugural world champs in 1973 to 1998. The U.S. then won three straight from 2005 to 2009, followed by bronze in 2011 and silver in 2013.

But Team USA was stunningly eliminated in the qualifying round in Kazan. It wasn’t even close. Although Jimmy Feigen, Anthony Ervin, Matt Grevers and Conor Dwyer tied Germany to win the final heat, their time of 3:16.01 was only good enough for 11th place. China, swimming 3:15.47, was the eighth and last qualifier.

Team USA redeemed itself in Rio. Feigen and Ervin, joined by Ryan Held and Blake Pieroni, qualified second with a time of 3:12.38, surpassed only by Russia in 3:12.04. In the final, Dressel, Phelps, Held and Adrian easily won the gold with a time of 3:09.92 ahead of France (3:10.53) and Australia (3:11.37).  


5. Can Lilly King hold off Yulia Efimova of Russia in the women’s breaststrokes events?

And will there be any finger wagging? The two exchanged finger wags in Rio after King said she didn’t agree with Efimova being allowed to compete after two doping suspensions.

King defeated Efimova of Russia in the 100 breaststroke, with Katie Meili of Team USA winning the bronze. Efimova also won silver in the 200 breaststroke, the only event in which an American did not make the final at the 2016 Olympics.

Efimova, who was booed in Rio, is the defending champ at worlds in the 100 and earlier this season became the first woman to break 2:20 in the 200.

She and King will also go head-to-head in the 50 breaststroke, which is not an Olympic event.


6. What’s this whole mixed relay thing about – and does it matter?

Mixed relays were a bit of a novelty when they were introduced at short course world championships in 2014 and then long course in Kazan two years ago.  Two men and two women compete for each team, but the order is up to each team. The U.S. won the 4x100-meter mixed freestyle in 2015 with an all-star cast of Lochte, Nathan Adrian, Manuel and Missy Franklin. Team USA won the silver in the 4x100 mixed medley.

It was announced last month that the mixed medley relay was added to the Olympic program for Tokyo 2020. Each team will seek a strategic advantage in the composition of its relay, with some putting men in the earlier legs to get ahead and others saving a strong male freestyler for the last lap. Imagine Manuel for the U.S. on the final leg against No. 1-ranked Duncan Scott of Great Britain.