BRIDGE the World (071-911 0900) is offering a novel journey in which passengers bridge some gaps themselves. You make your own way to Istanbul, where your nearly-round-the-world ticket comes into effect. You then fly to Athens on Olympic Airways and connect to Bangkok, cross the Equator to Sydney, and traverse the International Date Line to San Francisco, from where you drive down to Los Angeles to pick up a flight to Mexico City and on to Miami. You pay extra to fill in the gap to New York, where the final flight back to Heathrow awaits. The fare for this epic journey is pounds 898.