Though all of us are all sensitive to heat, and quick to react when it climbs above our comfort levels, our knowledge of how it might affect our health doesn't really go beyond sunstrokes and fainting spells.
The hardest climbing has only recently weighed into the new grade of 5.15 and then usually for single-rope-length sport climbs, which even then climbers may spend weeks or months attempting to overcome.
The term "big wall" is generally used by climbers to describe some of the world's longest climbs – usually predominantly on rock involving up to 30 rope lengths, and on which most climbers would expect to spend days climbing.
Some sterling work being done by the domestiques today to keep the pack together - not least Geraint Thomas, who has hauled Team Sky over the last two climbs.
Here's our own cycling doyen Will Fotheringham with his preview of today's stage: The Tour won't be won in Steel City but one of the favourites could lose it here, as the series of short steep climbs and some abrupt, narrow and very technical descents – equally difficult, particularly if the roads are wet – will make for a demanding finale, where a crash or a puncture could be very costly.
Facebook Twitter Google plus Share Share this post Facebook Twitter Google plus close 2.17pm BST14:17 As you can see on our snazzy interactive graphic at the top of the page, the second half of this race features seven categorised climbs – starting with the two Category 3 climbs of Ripponden and Greetland, just 8km apart, which are coming up imminently.
The former president has been accused of upstaging his wife, Hillary Clinton, as she climbs toward the pinnacle of power he once occupied.
The problem with bottom-up counts, like the FBI collection that begins with police records, is a severe attrition rate for data as it climbs toward the national light, as deaths go unreported or unrelayed from one level to another.
Ukip climbs back four points from a miserable score last time, to reach 11%.
There are eight categorised climbs including the classic, exposed ascent of Holme Moss.
Clancy said last year's Tour de France had taught the continental riders not to dismiss Yorkshire's lumps and bumps compared with the famous Alpine climbs: "They've learnt from last year that even if a stage might look quite flat on the profile, it really isn't".
