The Borlee brothers are perhaps the most famous twins in athletics at the moment, and the 400m runners are set to make history at the World Championships in Moscow.

When Jonathan and Kevin Borlee line up for the 4x400m relay alongside younger sibling Dylan, it will be the first time in the history of the championships that three siblings have all competed together in the same race.

While Dylan will be making his Worlds debut, Moscow will be Kevin’s third championships and Jonathan’s second. Kevin took bronze in Daegu two years ago as Jonathan finished fifth.

The Belgian twins—whose older sister Olivia won Olympic silver in 2008 and World bronze in 2007 in the 4x100m relay—are expected to be among the medal challengers again; not only in the individual event, but in the 4x400m relay too.

The Borlees aren’t the only set of twins in Moscow; there are three sets in the race-walking events alone!

Joao and Sergio Vieira will represent Portugal in the men’s 20km walk, Chile’s Edward and Yerko Araya will contest the 50km and 20km walks respectively, and Kazakh twins Ayman and Sholpan Kozhakhmetova will both compete in the women’s 20km walk.

Other twins in Moscow include Slovak jumpers Jana and Dana Veldakova; Jake and Zane Robertson, distance runners from New Zealand, and Algerian middle-distance runners Imed and Abdelmedjed Touil, who will compete in the 1,500m and 3,000m steeplechase respectively.

Aside from twins, there are many other sets of siblings set to compete at the Moscow event. Three reigning Olympic champions will be joined on their national teams by their younger siblings.

Olympic pole-vault champion Renaud Lavillenie is on the French team alongside younger brother Valentin. Three-time Olympic gold medallist Tirunesh Dibaba will be cheering on younger sister Genzebe Dibaba in the 1,500m, while World and Olympic discus champion Robert Harting will have his younger brother Christoph for company on the German team.

Kenya’s Bethwell Birgen will be a medal contender in the men’s 1,500m, while his brother Bernard Koech will have ambitions of a podium finish in the marathon.

Luis Rivera, the current world leader in long jump, will be one of Mexico’s best chances of a medal. He will be making his World Championships debut, but it will be the second Worlds appearance for his brother Edgar, who hopes to improve on his performance from two years ago in Daegu where he finished 26th in high jump qualifying.

Unusually, sisters Mimi and Almensh Belete will both be in Moscow but representing different countries. The former Ethiopians have switched allegiance, with Mimi now representing Bahrain and Belete running for Belgium.

There are also sprint hurdlers Shermaine and Danielle Williams from Jamaica and Thomas and Pascal Martinot-Lagarde from France.