The landscape of Etna starts to change, the vegetation thinning. Dennis, Dumoulin, Froome all within touching distance of each other.

The Colombians joined at the front by De Marchi and Ben Hermans. Froome only has Elissonde with him in the denuded peloton, Sanchez working it for Astana, 50 seconds back...

Two Colombians teaming up here - national champion Henao, of Team Sky, joined by comeback kid Chaves...

Two Astana men on the front, Froome sitting on Kenny Elissonde's wheel. Up the road, Gesink was pushing the break - but now BMC's Alessandro de Marchi has a little pop...

The break at 1' 20" with 15km to go, but it's spitting riders out the back - three Sky men pushing the pace at the elongated nose of the peloton, panic crackling in the warm Sicilian air.

Ouch!published at 15:31 British Summer Time 10 May 2018

15:31 BST 10 May 2018

Crash in the peloton, and Laurens ten Dam has gone down in that - he's one of Dumoulin's key lieutenants, Bora-Hansgrohe's Davide Formolo also caught up - all a bit slow motion, and they both look okay, but they'll have to chase back hard to get back on now.

Into the village of Ragalna, 18km to go, Etna just three km away.

Astana's Colombian Miguel Angel Lopez had another shocker on Wednesday, hence the need for emergency action. Michelton-Scott driving it too, Sky with a couple of men keeping it ticking over. The top of Etna tucked away in cloud, and it's fresh up there this afternoon, which is at least better than the swirling winds that can work across the volcano's harsh slopes.

And as it does so the gap starts to shrink - down to one min 45 secs now as we rattle through the town of Paterno and on towards Belpasso.

The reigning Giro champ and race favourite rolling along, his front wheel alongside the rear derailleur of Chris Froome. Simon Yates not too far all, a collective deep breath before the flat-out efforts to come.

Image source, AFP

Here's our race leader, looking to prove to the doubters that's ready to convert into a genuine GC contender. The next hour should tell us a great deal more.

Image source, AFP

...and so 15km to go until the road heads properly up. The break holding at 2' 16", plenty in there to keep it ticking along. Bahrain-Merida at the front of the peloton, Katusha doing their share in their distinctive Burnley FC colours.

General classification after stage five:

1 Rohan Dennis (Aus/BMC) 18hr 29min 41secs

2 Tom Dumoulin (Ned/Team Sunweb) +1sec

3 Simon Yates (GB/Mitchelton-Scott) +17secs

4 Tim Wellens (Bel/Lotto Fix All) +19secs

5 Pello Bilbao (Spa/Astana) +25secs

6 Maximilian Schachmann (Ger/Quick-Step Floors) +28secs

7 Domenico Pozzovivo (Ita/Bahrain-Merida) Same time

8 Jose Gonçalves (Por/Katusha-Alpecin) +32secs

9 Thibaut Pinot (Fra/Groupama-FDJ) +34secs

10 Patrick Konrad (Aut/Bora-Hansgrohe) +35secs

Selected others:

20. Chris Froome (GB/Team Sky) +55secs

35km to go, and Robert Gesink an interesting one in that break - came back from that heart operation in 2014, decent enough climber, no threat in the GC - might fancy a pop at this should the opportunity arise.

15km up Etna, an average gradient of 6%, a maximum of up to 16%. We call it a summit finish; with the Etna being an active volcano, the summit in this case is a good 1500m below the spicy one.

Britain's Chris Froome still 57 seconds down on race leader Rohan Dennis after his testing first five days of racing, and he's been back to the team cars for something - not sure if that was a mechanical, but he's working his way back with a little surreptitious slipstreaming. Chaves being in that lead group makes it interesting - he's the team-mate of Britain's Simon Yates, currently third in the GC, so is he there to support or to have a crack?

Big old group 2 mins 20 secs out front - the gap is closing, but most of the GC-contending teams have riders in it - Sky with De La Cruz and Henao, Michelton-Scott with Haig and Chaves. Can't see it staying away, mind - reigning champion Tom Dumoulin's BMC team working hard at the front of the peloton.

164km in the stage today, just under 50km to go, but it's the fun stuff - and the first summit finish of the day. Once through the town pf Paterno, it's all about the long climb up to the Astrophyiscal Observatory, and an exposed slog that could cause a major shake-up in the race for the maglia rosa.

Welcome to the punchy part of stage six of the Giro - and it's shaping up as a thriller.