Ones to watch at the swimming world championships
After a poor Rio Games, the "Professor" is back as the No.1-ranked 100m freestyler in the world. Snatched his fourth national title from Olympic champion Kyle Chalmers in April, but the Queenslander is still searching for a first world title.
Having claimed her 21st Australian title in April, the veteran backstroker and medley swimmer will represent Australia at her sixth world championship. The Queenslander won three gold - including two individual - in Kazan two years ago.
The 400m freestyle champion from Rio is fresh from claiming a rare treble at the nationals, winning the 200m, 400m and 1500m freestyle - matching Grant Hackett's effort from 2008. The Victorian's best result at the worlds is 800m bronze in 2015.
Keep an eye out for the 16-year-old from Tasmania, who collected the 400m and 800m freestyle crowns at the nationals, and finished runner-up behind Emma McKeon in the 200m, earning herself three individual swims in Budapest.
The younger Campbell sister finally has her first national titles - the 50m and 100m freestyle, which are usually dominated by sister Cate. But the Queenslander is the reigning 50m and 100m freestyle world champion from Kazan. Cate is taking some time out.
Another who missed out on the ultimate success at the Rio Olympics, forced to settle with a silver medal and a fourth-placing, the Queenslander will look to defend his two world championship titles from Kazan in the 100m and 200m backstroke events.
The four-time Olympic gold medallist will look to repeat her 200m, 400m, 800m and 1500m freestyle clean sweep from Kazan. The American looks unbeatable in the 400 and 800, but super Swede Sarah Sjostrom will provide a real challenge in the 200m.
With no Kyle Chalmers, fellow Aussie Cameron McEvoy is favourite to take out the blue riband 100m freestyle. But Scott will be right there taking it up to him as the first Brit to ever touch the wall under 48 seconds. He will represent Scotland on the Gold Coast next year.
Only just turned 17, the Canadian became the first Olympic champion born in the 21st century. She was also the the first Canadian to win four medals in the same Summer Games. She now has the chance to back up her Olympic gold in the 100m freestyle with a world title.
With Michael Phelps racing sharks in retirement and Ryan Lochte "dancing with the stars" while suspended, these worlds will be the first major international meet not to feature either since 2000. So can the US continue its domination of the 200m IM? It'll be up to Kalisz.
Competing in her home pool, the Hungarian "Iron Lady" will look for another dominant display after securing three gold (in both IMs and the 100m backstroke) at the Rio Games. While Aussie Emily Seebohm is a threat, US star Missy Franklin is out injured.
The American-based Singaporean, who beat Michael Phelps to glory in the 100m butterfly in Rio to collect his country's first ever gold medal, will contest the 50m, 100m and 200m fly, and the 100m freestyle. He wants to break Phelps' 100m fly world record of 49.82sec.