About 1,900 people have been invited to London for Prince William and Catherine Middleton's royal wedding but official estimates are that more than 600,000 additional guests will be in the city on April 29.
Just like the Royal Family, London's airports, ground transportation system, police and tourist industry are all getting ready.
For travellers to London — flights and rooms are still available — Frommer's editor Mark Henshall advises that planning is critical. His key recommendation for London visitors is to "have an idea for the wedding day and a couple of backup plans," he told CBC News.
How to get there, where to stay
London's usually busy airports are expected to be a little busier for several days before and after the wedding but there's no expectation that will lead to significant delays.
Henshall advises wedding travellers also consider staying outside London and getting an early train to the city on the big day. Even Paris is not too far away, with a trip via the Eurostar train just 2.5 hours to central London.
Some packages with accommodation outside London include transport to the city on April 29.
Ted Flett is already in London for the Royal wedding. Normally he works in Toronto managing public relations for VisitBritain, the U.K.'s official tourist board. He has been seconded to their London office to help with the international media crews that will be there to cover the wedding.
Flett told CBC News, "Roads, pathways and sites could be easier to navigate with Londoners perhaps departing and outside the city."
The government has declared April 29 a bank holiday and with the normal holidays on Good Friday, Easter Monday and May Day (May 2 this year), many locals can take off for 11 days, missing just three days of work. So it will be "prime time for Brits to be on the move," Flett said.
The April 29 bank holiday also means that very few business travellers will be staying in London, freeing up rooms.
For tourists on a tighter budget, Mark Henshall suggests staying in east London rather than the more common west London hotels. Large parts of east London are being revitalized for the 2012 Olympics.
Henshall, who was the commissioning editor for Frommer's The Royal Wedding e-book, also suggests that still less expensive but sparser accommodations are available at university residences like the London School of Economics because of the Easter break.
Where to be, April 29
For people hoping to get a spot along the wedding procession route, weather, walking and water are key for Flett. Two weeks ahead, the long-range forecast for April 29 is partially cloudy with a high of 14 degrees.
If it should turn out to be sunny, Henshall advises heading for a spot like Hyde Park, which has tree cover. And it's London so pack an umbrella.
Henshall recommends having a back-up plan should your preferred spot not work out.
Be prepared to walk more than expected. The London tube will be operating and no station closings are planned but it could happen, or there could be limited access.
There will be road closures and parking restrictions, beginning at 5:30 a.m. on the wedding day.
Security will be tight and the Met police have said they may carry out stop-and-search operations in the procession route area.
Neither Flett nor Henshall would stick their neck out on how early a visitor needs to arrive to get to a spot along the procession route, but they both note there other places to soak up the wedding atmosphere.
Large screens will be set up in Hyde Park, St. James's Park and elsewhere. In Britain pubs are also an appropriate place to watch the live broadcast. (Pubs can stay open for extended hours April 29-30.)
After the wedding the crowds around Buckingham Palace are expected to grow in expectation of a traditional palace balcony appearance by the newlyweds.
All around London and Britain local communities are organizing street festivals for April 29. Castles in the London area will be holding events.
Other options include afternoon teas and dinner banquets at hotels and top restaurants.
Anti-monarchists party, too
There are events for opponents of the monarchy, too. Republic, the U.K.'s leading anti-monarchist group, has two parties set for the 29th, the largest at Red Lion Square (near Holborn tube station).
The next day in London, there's a convention of the Alliance of European Republican Movements.
Westminster Abbey will be closed to the public for the week before the wedding but there will be extended hours the day after, with the Abbey still displaying its full floral regalia from the wedding.
Flett said it "will be quite special for people to be able to take in."
Events outside London
Both Flett and Henshall advise wedding travellers to check out events outside London. Frommer's What to see and do webpage for the Royal wedding even has as it's first link a "Get out of London!" feature.
And there are other events. Stratford celebrates William Shakespeare's birthday starting April 23, the Cheltenham Jazz Festival opens April 27 and the next day in Scotland the Speyside Whisky Festival begins. In Spalding on April 30 there's a flower parade of tulip-decorated floats.