London observes Greenwich Mean Time, which runs 5 hours later than Eastern Standard Time. From late March till late October, British Summer Time is in effect, meaning that all clocks move forward one hour.

Since electricity in Great Britain runs at 240 volts, some international travelers may need to invest in a converter for personal hair dryers, shavers, and the like. Also required is an adapter that fits British outlets.

Air-conditioning is not a given in London, so inquire of your hotel before booking, or plan your vacation to avoid summer's hottest months.

Unlike many European countries, Great Britain opted not to adopt the euro. Thus, the pound sterling remains the basis of the monetary system.

Some higher-end restaurants have taken to billing a cover charge of £1-2 per table. It functions as a standard charge and will appear on the final bill. Some restaurants also require a credit card to hold a dinner reservation.