The World Indoor Athletics Championships start in Birmingham on Thursday.
Here, Press Association Sport looks at five athletes to watch over the next few days.
Laura Muir (GB and NI)
A year ago Muir claimed a special double when she won the 1500 metres and 3000m at the European Indoor Championships in Belgrade.
They were her first major international titles and the Scot will be looking to do it again on the world indoor stage in Birmingham.
She came fourth in the 1500m at the world championships in London last year, along with a sixth place in the 5000m.
Muir will miss April’s Commonwealth Games though as she studies for her final veterinary exams at the University of Glasgow in May.
Katarina Johnson-Thompson (GB and NI)
The last time the 25-year-old competed in a pentathlon, at the 2015 European Indoor Championships in Prague, she finished just 13 points short of Nataliya Dobrynska’s world record tally of 5013.
That early promise is yet to yield major medals though after she finished 28th at the 2015 world championships, sixth at the 2016 Olympics and fifth at last year’s world championships in London.
She is out to claim her maiden global title having moved to France almost two years ago to be trained by Bertrand Valcin.
With Belgium’s world and Olympic champion Nafissatou Thiam absent it is a golden chance for Johnson-Thompson to shine.
CJ Ujah (GB and NI)
Part of the men’s 4x100m world title-winning squad last summer Ujah opted to miss the Commonwealth Games to focus on his indoor goals.
He won the 60m British title on the same track in Birmingham in February but only came fifth in 6.57 seconds at the Indoor Grand Prix in Glasgow on Sunday.
Ujah failed to reach the world championships 100m final by 0.02 seconds but did win the prestigious Diamond League final in Zurich last year.
He has said he is not scared of America’s Christian Coleman as the pair go head to head at Arena Birmingham on Saturday.
Christian Coleman (USA)
The American broke the 20-year-old 60m indoor world record when he clocked 6.34 seconds at the US Indoor Championships in New Mexico this month.
It eclipsed Maurice Greene’s mark of 6.39 seconds in 1998 and 2001, although Coleman’s run needs to be ratified by the IAAF, the world governing body.
The 20-year-old won world 100m silver ahead of Usain Bolt in London last summer, finishing behind controversial winner Justin Gatlin.
Coleman is the red hot favourite to win gold in Birmingham.
Genzebe Dibaba (Ethiopia)
The defending 3000m champion doubles up for the first time at the world indoor championships – running the 3000m and 1500m.
She has won three world indoor titles, 1500m in 2012 and the last two 3000m crowns.
Muir will be out to stop her but the 27-year-old has proved almost unstoppable indoors.
Yet Dibaba has some questions to answer after she came last in the 1500m in London, spectacularly failing to defend her title.