People who wish to see the Queen lying in state have been warned to brace for long queues and observe strict rules.
The Queen is lying in state in Westminster Hall, with the doors open 24 hours a day.
Her Majesty's coffin will spend four days in Westminster Hall before the state funeral at Westminster Abbey on Monday.
This is what you need to know if you wish to see her coffin.
The route begins on Albert Embankment, next to Lambeth Bridge, before snaking down the River Thames to Southwark Park - a distance of more than four-and-a-half miles.
Those in the queue will pass famous landmarks including the London Eye, National Theatre, Tate Modern and HMS Belfast.
You can expect:
• Extra toilets and water fountains made available along the route
• The Southbank Centre, National Theatre and BFI Southbank extending opening hours to provide refreshments
• Cafes and other local businesses to stay open longer
• More than 1,000 volunteers, stewards and police officers on hand
• BFI Southbank to show archive footage of the Queen on an outdoor screen
What should you expect if you visit?
Visitors go through airport-style security and those waiting will be issued with numbered wristbands, allowing them to leave temporarily to use nearby portaloos or to buy supplies.
Regular updates on queue length, estimated waiting time and when it closes are being provided on government social media accounts.
The entire route has step-free access. However, a separate route begins at Tate Britain, where timed entry slots are issued for those who need them.
Government advice urges those with pre-existing medical conditions to "check the guidance, plan accordingly and be prepared for significant wait times, including possibly overnight".
It adds: "Members of the public are also urged to check for travel updates, plan their journey and check times for last services."
Guide dogs, hearing dogs and other official assistance dogs are allowed into Westminster Hall, and British Sign Language interpreters will be available.
It is understood that no proof of disability will be required for those wishing to see the Queen's coffin.
Stewards are asked to look out for anyone struggling, and take a pragmatic approach in assisting them.
What can you take in with you?
There is a strict bag policy, with each person allowed one small bag only.
It must be smaller than 40cm x 30cm x 20cm, with a simple opening or zip.
Anyone who has to bring a bigger bag will have to leave it in a drop facility - but space is limited and there is no guarantee of storage.
There are limited places to buy food and drink along the queue route, so the public are encouraged to bring their own supplies. But they must be consumed, or disposed of, before entering the palace.
A portable mobile phone charger is advised.
What items are banned?
Flasks or water bottles are not allowed, unless they are clear.
Flowers and other tribute items, including candles, soft toys and photographs are also prohibited.
Flowers only should be taken to the dedicated area in Green Park.
Sharp items, paint sprays, padlocks, chains, climbing gear and any other hazardous items are banned.
Banners, placards, flags, advertising or marketing messages are not allowed either.
All camping equipment - including coolers, hampers, sleeping bags, blankets and folding chairs - are not to be brought, as well as non-foldable pushchairs.
Extra facilities along the way
An army of 1,000 dedicated volunteers, including more than 100 scouts, stewards and Metropolitan Police officers will be on hand to help, alongside facilities including toilets and water fountains.
But take advantage when you see them, as staff involved in the logistics told Sky News they were worried there would not be enough, saying: "There will be queues within the queues to get to the portaloos.
"There might be a lot of crossed legs. I would advise people to have very little liquid. It's a practical issue."
St John Ambulance will operate eight stations along the route to provide first aid if it is needed, and there will be emotional support from the Samaritans and the Salvation Army.
There will be welfare support from the Red Cross, and Lambeth Palace will arrange a street pastor multi-faith service.
How must you behave?
People are warned to "respect the dignity of this event" and remain silent in the Palace of Westminster.
Antisocial behaviour, including queue-jumping, excessive consumption of alcohol or drunken behaviour will not be tolerated.
People are warned not to film, take photographs or use mobile phones in the security search area or within the palace.
You cannot bring tents or gazebos, or light barbecues or fires.
London should be dry from Wednesday until the funeral, the Met Office has said, with less than a 10% chance of rain.