Different procedures in different places, sometimes holding (circling) is favoured, in other places sending aircraft off on indirect routes is favoured.

The grand-daddy of them all is indeed London Heathrow, which has four standard holding points in the four corners around London airspace. Sometimes these can become full and further holding points further out are also used. Other UK airports use the same technique. Under normal conditions you can expect maybe once or twice round the block at Heathrow, but if something goes wrong (even just one go-around) then things can start to back up. The normal situation shouldn't make for late arrivals as the schedules allow for it; in fact much of the holding at Heathrow arises from aircraft arriving a few minutes early.

The US favours sending aircraft off on long off-line routes to achieve the same thing; at Miami for example you seem to be sent off over the Everglades, a long run out and then a long run back. It depends on the length of flight as well; if Heathrow gets into trouble an inbound domestic flight can have departure delayed but this is not possible of course for intercontinental flights which were in the air long before things started to happen.

Holding is usually over a VOR radio beacon. Doing a "classic" VOR hold accurately is one of the more challenging aspects of flying, doing the oval just by listening to radio blips from the beacon and using your stopwatch (yes, even on a 747) and the aircraft instruments. Actually more modern aircraft have the holds in their flight management computer; the crew can just punch it in and then sit back while the aircraft flies it immaculately. In a really accurate hold you may feel a slight tremor in the aircraft as you fly through your own wake turbulence from several minutes previously at the same point. I've been with a guy doing the hand-fly stopwatch method and we got this. He was pleased with himself !