The story of Eau

The sympathetically reconstructed Spa is quick – Mark Webber's fastest lap was 142.587mph – but it's not as quick as its 'daddy' used to be. 
There was a time when tracks – and I'm talking trees-and/or-houses road circuits, not banked ovals like Brooklands' Outer Circuit, and not there-and-back blinds like Berlin's AVUS – cared naught for safety nor health and instead blatantly vied to be the outright quickest. Spa, you might be surprised to read, wasn't really at the races in this respect. So it took drastic action.
The original 'Eau Rouge' was hardly white-knuckle. Two sharp lefts connected by a hairpin right over a bridge, it was lumbered with a tardy nomenclature, too: Virage de l'Ancienne Douanne. Ooh, feel the speed. In fact, it was sufficiently slow for Rudolf Caracciola, on his way to winning the 1935 Belgian GP for Mercedes-Benz, to smell a spectator's wisping cigar smoke.
That changed in 1939 when a radically reprofiled road cut a lazier yet much faster ess down, across and up out of the valley. Red-blooded, this was the real Eau Rouge. Its ramping effect, however, was diluted by the rain that fatally caught out Dick Seaman on the opposite, return leg of the circuit: Hermann Lang, Mercedes W154 (with M163 engine), 101.4mph.
By 1950 and the inauguration of the (second) World Championship, there had been further surgery: Stavelot, scene of a tight right-hander on the outskirts of the town, had been replaced by… new Stavelot, a fast, sweeping, helpfully cambered right that opened out invitingly upon its exit. Giuseppe Farina's Alfetta thus uncorked a 115.1mph race lap, faster than team-mate Juan Fangio's subsequent best at Reims (112.3mph), but slower than the Argentinian's times-topper at Monza (117.45mph).
Reims' rapid response was to bypass the photogenic but nadgery Gueux village section with a flat-maybe right of its own, a new section of track then linking it to Muizon, a tight-ish right that usefully extended the subsequent hidden-dip fang along Route Nationale 31 towards Thillois. Merc rookie Hans Herrmann lapped this revised layout at 121.455mph in 1954, the first year of 2.5-litre Formula One (With apologies to DB-Panhard, I think we can helpfully forget its 750cc-supercharged sub-clause.)
Monza, suddenly lagging in the speed stakes, went several steps beyond in 1955 by merging a steepling new banked oval with its long-established parkland blat: Stirling Moss, Mercedes-Benz W196 Stromlinienwagen, 134.029mph.
Trumped, Spa continued to smooth, ease, straighten and neaten, and had (un)comfortably topped 130mph by 1958. 
By 1960, it was nip and tuck: 
Spa: 135.434mph
Reims: 135.16mph
Monza: 136.731mph – though no doubt this fastest race lap would have been higher still had not the British teams boycotted the race in protest at the unsubtle reinsertion of the oof-ow-ooer oval.
1966's 3-litre 'Return to Power' marked Reims's final F1 hurrah, Lorenzo Bandini circulating at 141.435mph before having to jury-rig his Ferrari's broken throttle with a stretch of wire snaffled from a fence. Team-mate 'Lulu' Scarfiotti's fastest lap at Monza in 1966 was 'only' 139.203mph.
These, though, were put into context in 1967 when Dan Gurney's Eagle clocked a 148.848mph race lap at an overcast but this time thankfully dry Spa. (Jim Clark's Lotus 49 had cracked 150mph in practice.) It's little wonder that wings sprouted there in 1968.
It couldn't last, of course. Spa was given a chance to redeem itself by the resurgent and bullish GPDA, but its extra Armco and unsatisfactory Malmédy chicane of 1970 could only ever be a stay of execution: Chris Amon, March 701, 152.077mph. Nivelles-Baulers, 2.3 miles of anodyne anonymity that not so long ago morphed into the trading estate that it was always surely destined to become, beckoned.
The 'war' won in 1971 – Henri Pescarolo, March 711, 153.489mph – Monza was no doubt less concerned about having to then dam its slippery quick stream with a chicane or two.