The 21st edition of the quadrennial Commonwealth Games begin this Sunday, April 8, in Gold Coast, Queensland, Australia. The Games encompass 15 different sports contested among 71 different teams, all of which are member states of the former British Empire. Below, we detail several attention-grabbing events to be contested at this year's championship.

1. Olympic Champion Showdown Between Elaine Thompson & Shaunae Miller-Uibo

One of the best head-to-head matchups of the Games will be in the women's 200m final, which will feature Elaine Thompson of Jamaica and Shaunae Miller-Uibo of the Bahamas. Both women earned gold medals at the Rio Olympic Games; Thompson won the prestigious 100m/200m double while Miller-Uibo's dramatic, last-minute lean to win the 400m final was one of the most memorable moments in Brazil.

The champions will meet in the middle of their specialties for the 200m. 

Thompson concentrated on the 100m in place of the 200m last season, though a sudden illness hampered her at the world championships and she did not earn a medal. 

Miller earned bronze in the 200m at worlds and did not medal in her usual specialty, the 400m, though she went on to win the IAAF Diamond League final in the 200m ahead of Thompson, who bounced back the following week to win the 100m Diamond League final in Brussels.

Miller-Uibo gets the nod from us as the CG favorite, given her two 200m wins over Thompson last summer; she also set a Bahamian national record of 21.91 last year at the Prefontaine Invitational, while Thomspon ran 21.98 for third.

A notable absence from the 200m is Nigeria's Blessing Okagbare, the defending Commonwealth Games champion whose 22.04 (+0.5) season-best is the fastest time in the world this year and established a new African record. 

Watch Blessing Okagbare, effortlessly race to a new 200m PB & AR of 22.04s. Definitely, there's more speed in those legs. #GC2018 pic.twitter.com/ya3SdkCPyw

— Nigeria Athletics (@NGAthletix) March 28, 2018

The former UTEP Miner, who was coached in college by Harvard's Kebba Tolbert, will race only the 4x100m relay. She was honored as Nigeria's flag-bearer in the Commonwealth Games opening ceremony.

2. Distance Races Headlined By World-Beaters Caster Semenya, Elijah Manangoi, Timothy Cheruyiot, Nijel Amos, Hellen Obiri

Two-time Olympic 800m champion Caster Semenya of South Africa will chase the middle-distance double in Australia with both the 800m and 1500m events on her queue. While it's unlikely that anyone will challenge her in the 800m—Semenya has a 21-race win streak in that event—she's not as dominant in the 1500m. 

Kenya's Beatrice Chepkoech could potentially pull off an upset, as she has 4:02 1500m and 8:59 steeplechase credentials—though she was just seventh in the 1500m at the IAAF World Indoor Championships in March. She won the Kenyan CG Trials in 4:04.63, the second-fastest in the world this year behind Semenya.

Semenya's national titles in Pretoria established world-leading marks of 1:57.8 and 4:02.63.

Caster Semenya will be the official flag bearer at #GC2018 in the opening ceremony on Wednesday. The two-time Olympic gold medalist will be making her first appearance at the games. pic.twitter.com/Ft7TBHl25f

— SuperSport (@SuperSportTV) April 1, 2018

On the men's side, Kenya's Elijah Manangoi and Timothy Cheruyiot should put together a thrilling 1500m final. They earned gold and silver, respectively, at last summer's 2017 IAAF World Championships.

Manangoi has the superior kick, which aided him to the world title, while Cheruyiot is a strength runner who can win races wire-to-wire, including the 2017 Diamond League final over his friendly rival. 

Cheruyiot recently defeated Manangoi to win the CG Trials in Nairobi, 3:34.84 to 3:35.42.

My race yesterday. Very happy for the next chance to represent Kenya. Elijah, Kumari congrats. Thanks @dennisokeyo pic.twitter.com/cOd8d80ppf

— Timothy Cheruiyot (@tim_cheruiyot) February 18, 2018

Botswana's Nijel Amos enters the Commonwealth Games on a hot streak after opening the outdoor season with a 45.94 400m and 1:44.65 800m, the latter of which was at last weekend's Stanford Invitational. Amos is the reigning CG champion, and while he finished fifth and outside the medals at the world championships last summer, he won five Diamond League races in 2017—including the final in Brussels.

Watch Nijel Amos run 1:44.65, a Stanford Invitational meet record:

Amos will be challenged by a slew of quick Kenyans, who have combined with him to run the four fastest times in the world this year: Jonathan Kitilit (1:44.04 SB), Wycliffe Kinyamal (1:44.72), and Cornelius Tuwei (1:44.91).

If you're looking for some homegrown talent to cheer for, young Aussies Joseph Deng and Luke Mathews could be in contention with season-best marks of 1:45.71 and 1:45.83. 

The women's 5K is headlined by Hellen Obiri of Kenya, who dropped Ethiopia's Almaz Ayana—the world record holder for 10K—in the London world final last summer like she was on the middle school track team.

3. Former (And Current) NCAA Stars Take On The Future Of The Sport, Joshua Cheptegei, In 5K/10K

Uganda's 21-year-old Joshua Cheptegei headlines the men's 5K/10K fields after his impressive run at last summer's IAAF World Championships, where he took runner-up honors in the 10K to Mo Farah. 

He set PBs last year in both the 5K and 10K: 12:59.83 and 26:49.94, respectively, which make him the class of the field.

Cheptegei's biggest competition will likely come from Mo Ahmed of Canada, who is also entered in the 5K/10K double. Ahmed competes for the Bowerman Track Club and is a graduate of the University of Wisconsin.

At the London worlds, the former Badger was sixth in the 5K final and eighth in the 10K final. In the Rio Olympic 5K final, he finished just outside of the medals in fourth.

American track fans will also be interested in the fates of a few other NCAA products, including a current Badger—Wisconsin junior Morgan McDonald, who won the Australian National Trials 5K. 2016 NCAA XC champion Patrick Tiernan, formerly of Villanova, will represent Australia in the 10K; NAU alum David McNeil of Australia will race the 5K and 10K; and Arkansas alum Kemoy Campbell of Jamaica will contest the 5K.

New Zealand's Zane and Jake Robertson are also in the 10K.

4. Redemption For Isaac Makwala

Botswana's Isaac Makwala was probably the most talked-about athlete who did not win a medal at last summer's IAAF World Championships.

After a stomach bug drew suspicions of the norovirus, the top-ranked Botswanian sprinter was forced to withdraw from the 400m final and 200m heats at worlds; later, he was allowed to race in a special, solo 200m heat to qualify for the final, did push-ups in front of a screaming London crowd, and ultimately placed just sixth in the 200m final.

But that was last year. 

This year, one of the best sprinters the world has ever seen seeks to redeem himself, starting with his first career gold at the Commonwealth Games in the 400m. 

The reigning Diamond League champion ran 45.03 in Pretoria in March.