Did you know that Selfridges is on the same road as the Brecon Beacons? That you can see the Scottish Parliament from a road that passes through Islington? Or that you can walk directly from Lambeth North to Brighton Pier without setting foot on more than one road?
Then there is the blessed junction outside St Paul's Tube station, where roads from two different countries meet. Head west along the A40 (beginning on Newgate) and you'll eventually reaches Wales. Choose the northern route past the Museum of London, and you can get into Scotland without leaving the A1.
Welcome to the surprising world of London's A-roads. We tracked a few of the more interesting ones down to their final destinations (with a lot of help from Google Maps and Street View).
The A1: Take Upper Street to another country
Upper Street in Islington is really badly named. It's actually part of the lower 0.5% of the A1, which stretches all the way up to Edinburgh. This most famous of A-roads begins at St Paul's and travels up past the Museum of London, along Goswell Road, through Islington and along Holloway and Archway Roads and then onwards past Welwyn and Stevenage to the north. Eventually reaching Edinburgh, the final stretches of Britain's longest route adopt the name London Road. Total length: 410 miles.
The A2: Take the Old Kent Road to Dover
The A2, as Old Kent Road is more prosaically known, begins at Borough Tube station as Great Dover Street. It is indeed old and Kentish, forming the southern part of the Roman Watling Street down to Canterbury and Dover. Its London sections pass through New Cross, Deptford and Blackheath before climbing Shooters Hill. There, the A2 dips down into Kidbrooke and Eltham on modern roads, but you can still follow the original Roman route by carrying on east on a dead-straight line through Welling and Crayford (A207). The two routes recombine near Bluewater before heading off into deepest Kent. Total length: 72 miles.
The A3: Take Borough High Street till you reach Portsmouth
Instead of heading east at Borough Tube, you might instead go south, down the A3, which eventually reaches Portsmouth. Along the way, it is variously known as Borough High Street, Newington Causeway, Kennington Park Road, Clapham High Street, Wandsworth High Street, Kingston Road and much else besides. Total length: 78 miles.
The A4: Take Fleet Street as far as Bristol
Call it the A4, and you have an unmemorable traffic route. Call it Fleet Street, Strand, Pall Mall, Piccadilly, Knightsbridge and Brompton Road, and you have some of the most famous streets in the world. This most notable of roads also comprises Cromwell Road (home of the V&A and Natural History Museum), the Hammersmith Flyover, and the Great West Road before heading out to Bath and Bristol, flirting the whole way, and occasionally commingling, with the M4. Total length: 130 miles.
The A5: Take Edgware Road... to Anglesey
Edgware Road and its northern continuations are perhaps the most obviously Roman route in London, heading in a perfectly straight line, save for an Elstree kink, all the way out beyond the M25. This is the northern stretch of Watling Street, the Anglo-Saxon name for the old Roman route out to the Welsh borders. Today, as the A5, it ventures as far as Holyhead in north-west Wales, although it briefly loses its name (becoming the A5183) just outside London. Total length: 260 miles.
The A10: Take Bishopsgate up to the Norfolk coast
One of the main thoroughfares through the ancient City of London, Bishopsgate formed part of Ermine Street, a Roman road that once led up to York (Eboracum). Sometimes called the Old North Road, it remains one of the straightest roads in London, beginning at Monument station, passing up through Bishopsgate, Shoreditch High Street and Kingsland Road, then on through Dalston, Stokey, Tottenham and Edmonton. Were you to follow the A10 (as it's officially designated) to its conclusion, you'd pass through Cambridge before coming to an end in King's Lynn, Norfolk. Total length: 161 miles.
The A13: Take Commercial Road out to some Essex mudflats
The A13 leads out from Whitechapel to Southend and Shoeburyness, whisking beachhut-hunting Londoners through many areas of industry and marshy desolation. You'd think there wasn't much more to say about this estuarine highway. You'd be wrong. Total length: 41 miles.
The A23: Take Kennington Road down to Brighton
A single road connects Lambeth North Tube station to Brighton Pier. The A23, as it's now known, is another old Roman road, a fact that becomes readily apparent if you follow its largely straight course on a map. Within London, the A23 follows Kennington Road, Brixton Road and Streatham Hill, before heading down through Norbury and Croydon. It then picks up speed by joining the M23 before relaxing back to its A-status on its way down to the coast. Total length: 52 miles.
The A40: Take Oxford Street... all the way to Wales
You guessed it, Oxford Street leads to Oxford. But it will also take you to Cheltenham, Gloucester and over the Brecon Beacons to Fishguard in Wales.
The stretch known as Oxford Street is about a mile and a half long, although the distance can seem much greater on a Saturday afternoon. This is one of the capital's oldest thoroughfares, following the line of an ancient Roman road that led to Colchester in the east and Hampshire in the west. Today, it's also known as the A40.
Within London, it begins just north of St Paul's, runs over Holborn Viaduct and along Holborn and New Oxford Street, along Oxford Street, then north to the Westway, Western Avenue and the M40, and thence on to Wales. In days gone by, the A40 took the more satisfyingly straight route of continuing west from Marble Arch along Bayswater Road and Uxbridge Road, running along what is now the A4020. Total length: 256 miles.