Heathrow began commercial operations 50 years ago this winter. However, the airport acquired its present shape a decade later when the Queen opened the Central Terminal Area. And it was only 10 years ago that Terminal Four began operations. Now Heathrow Airport Limited (HAL), which runs the place, is pushing hard for Terminal Five.
As well as a floating population of 50,000 workers, up to 185,000 travellers use the place daily. Their numbers are boosted significantly by "weepers and wailers", the term used by HAL to describe people seeing off passengers, and "meeters and greeters".
Like a latterday Berlin, Heathrow is divided in two by a barrier. This separates landside from airside. Three ways to cross it: get a job at the airport; buy a ticket and fly somewhere; buy a ticket and don't fly somewhere. If you have a full-fare refundable ticket and only hand luggage, you may decide not to travel at any point up to and including the departure lounge.
The standard currency is sterling, but any of the dozens of bureaux de change will exchange foreign funds for you. A lesser-known currency is the Light Refreshment Voucher, issued when your flight is delayed by three hours or more. The pounds 6 LRV can be spent within the airport on food or drink, but not alcohol.
Eating and drinking
So where to spend it? You might wish to consult the diners' guide Where To Eat Well At Heathrow Terminal One. To compile this and other documents on Britain's airports, Egon Ronay's inspectors have tested 18,500 items of airport food and drink (at a rate, says the publication, of one item per hour, which sounds a bit slovenly to me). The terminal's best according to Egon are Garfunkel's and Haagen-Dazs, each of which earns maximum marks for "best food and beverages at airport, helpful, friendly and efficient service and being exceptionally pleasant places with good atmosphere". According to me, Harry Ramsden's fish and chips, not to mention mushy peas and robust tea, travel well from Guiseley.
"No person shall sing, dance, shout or play a musical instrument in such a way as to give reasonable cause for annoyance to any other person", say the by-laws, which rather restricts the party potential. The guest list would need to be fairly carefully chosen in any case, since access to the Heathrow terminals is limited to "airline passengers and persons meeting or seeing off named passengers and authorised staff only". The Virgin Clubhouse is the closest approximation to a good time that you can have, but to gain access to Richard Branson's Terminal Three extravaganza you need to be in possession of an upper-class ticket.
Sport and recreation
If you feel like a hearty walk, check in for a flight departing from the new extension of Terminal Four. This is the longest passport control- to-gate stroll of all, taking a fit person, unencumbered by luggage, seven or eight minutes. An alternative is to fly to Dublin. The strangest structures at Heathrow are the people pipes that extend from Terminal One to the back end of Terminal Three. By the time you reach the gate, you may have missed the flight. Luckily, the link with the Irish capital is one of the two most intensive routes from the airport - the other is to Paris.
If you don't feel like a hearty walk, check in quick for Terminal Three. Most airlines there operate electric trolley services for tardy or tired passengers. However the word is that these services are currently under threat.
Six things you can't do at Heathrow ...
1. Stay at a hotel at the airport. Terminal Four has a Hilton attached and there are plenty on the northern perimeter, but nothing in the central area that you can reach without leaving the airport. Many other airports have hotels built in; Gatwick has one for each terminal.
2. Walk away. Pedestrians are banned from the tunnel out of the central area.
3. Have a haircut. Magicuts has recently closed down.
4. Be waited upon at a restaurant. The single most baffling omission is a decent waiter-service restaurant. Conducting business discussions in Garfunkel's does not seem quite right.
5. Listen to the local radio station - the idea was tried, but failed artistically (even at the world's busiest international airport, a list of flight delays palls rapidly) and financially, and has now closed down. BBC Radio News has studios in Terminals One and Four, though.
6. Take off between the hours of midnight and 6am.
1. Land at 4.30am (for example on British Airways from Hong Kong). The Tube starts running an hour later.
2. Read the local paper. Skyport News is free from dispensers in staff areas.
3. Worship. Each terminal has a multi-denominational chapel.
4. Get a free bus ride - to almost anywhere in and around the airport.
5. See the spire of Feltham church - the only visible sign of the world beyond the airport perimeter.
6. Take off - to one of 220 destinations worldwide.