Kazan: Ahead of the world swimming championships in Kazan, Russia, from August 2-9, here are five races to look out for in the pool at the Kazan Arena Stadium:
WOMEN`S 1500M FREESTYLE -- Final on Tuesday, August 4
US swim star Katie Ledecky set a world record in the Barcelona final two years ago and the 18-year-old Olympic champion promises to deliver another masterclass in the one-mile freestyle in Kazan.
Denmark`s Lotte Friis, who claimed silver in Barcelona, and New Zealand`s Lauren Boyle, who took bronze, will again be pushing for a podium place in the endurance event.
Australia`s Jessica Ashwood has posted the closest to Ledecky`s 15mins 42.23secs, the fastest time in the year so far and it will take a titanic effort to wrestle gold from the Olympic and world champion.
WOMEN`S 100M BACKSTROKE -- Final on Tuesday, August 4
As the reigning world and Olympic champion, this is Missy Franklin`s blue-ribbon event, but she faces a battle royal to hold onto her crown in Kazan.
Australian pair Emily Seebohm and Madison Wilson have both swum under 59 seconds this season to post the world`s fastest times.
Other challenges to the 20-year-old Franklin, who won six golds in Barcelona two years ago, come in the shape of US veteran Natalie Coughlin and IM specialist Katinka Hosszu, who is in the form of her life and set to swim multiple events in Kazan.
MEN`S 50M BREASTSTROKE -- Final on Wednesday, August 5
South Africa`s Cameron van der Burgh and Australia`s Christian Sprenger will resume their breaststroke battle in Kazan after they both won a world title in 2013.
World-record holder Van der Burgh took the 50m title in Barcelona two years ago, while Sprenger avenged his narrow defeat by one hundredths of a second by beating the South African over 100m.
Van der Bergh is the favourite, but Britain`s Adam Peaty will be looking to get amongst the medals after posting the fastest time in the world so far and took silver to the South African in last year`s Commonwealth Games final.
MEN`S 200 IM -- Final on Thursday, August 6
Reigning champion Ryan Lochte is the favourite to win his fourth consecutive world title in the event with USA swim star Michael Phelps not selected because of a drink-driving offense and Japan`s Kosuke Hagino, who has posted the fastest time this season, injured.
Lochte and Phelps have dominated the event since 2004 after Phelps won every major competition until 2008 as Lochte began his winning streak in 2009 and set the world record of one min 54.00secs in 2011.
The US pair are the only two swimmers to ever swim under 1min 55secs, which they have done a collective total of 14 times.
Despite Phelps` absence, Lochte is taking nothing for granted with Japan`s Daiya Seto and Brazil`s Henrique Rodrigues having both swum faster than him this season.
Great Britain`s Roberto Pavoni and China`s Wang Shun have also both posted faster times than Lochte this year while Hungary`s five-time Olympic medalist Laszlo Cseh will be a threat.
WOMEN`S 100M FREESTYLE -- Final on Friday, August 7
Australia`s Cate Campbell will have to deal with a sibling rival when she defends her world title from Barcelona 2013 in the women`s 100m freestyle.
If all goes to plan, Cate, who won gold at the 2014 Commonwealth Games and Pan Pacific Championships, will line up on the blocks in the final alongside her sister Bronte, the Commonwealth Games and Pan Pacs silver medallist.
This will be a fiercely-contested battle with Cate Campbell going into the heats with the joint fastest time this year of 52.69 alongside Dutch swimmer Femke Heemskerk, who joins her as the hot favourites.
Sweden`s Sarah Sjostrom is a potential medallist having also gone under 53 seconds this season.