Every April, the world-famous London Marathon draws almost 40,000 runners and thousands of excited spectators to England's capital city.
This year's race, which will take place on Sunday 28 April 2019, is expected to break new ground, bringing the total raised for good causes since the event's inception to well over £1 billion.
While no one can take away from the incredible effort put in by the runners themselves, many will tell you that it's the crowd in London that keeps them plodding on when the tiredness hits and their legs turn to jelly.
If you're one of the runners taking part in the race, you'll probably want to keep your focus on the road in front of you - and so you should, really.
But if you're planning on joining the crowd of spectators watching the 2019 London Marathon and cheering on the participants, here's a guide to the running route and what you can expect to see along the way.
8:55am: Elite Wheelchair Races
9:00am: World Para Athletics Marathon World Cup ambulant races
9:15am: Elite Women's Race
10:00am: Elite Men's Race, British Athletics and England Athletics Marathon Championships
Just after 10:00 am: The mass race begins!
The big mass race begins at 10am in the south part of Greenwich Park in southeast London.
The starting point is right near the National Maritime Museum and the Royal Observatory, a world-famous London landmark designed by Sir Christopher Wren, who also built St Paul's Cathedral and Kensington Palace.
This is the location of the Prime Meridian, the point against which all time and distance is measured around the world. Could there be a more fitting beginning to this epic race?
The assembly points at the start of the marathon are for participants only.
After setting off, the runners will head east toward Woolwich and around the Woolwich Dockyard. The race then passes Charlton and heads to Greenwich town centre and Cutty Sark, the legendary tea clipper ship on display near the River Thames.
If you choose to watch the beginning of the race in Greenwich, the party doesn't have to end after all the runners have set off. Why not take the Greenwich Foot Tunnel from Cutty Sark to the Isle of Dogs?
This funky pathway under the River Thames is a sight worth seeing on its own and will bring you close to mile 17.
For spectators who want to be near the beginning of the route, Woolwich is a prime spot. You can get the DLR (Docklands Light Railway) to Woolwich Arsenal Station (expect LOTS of people!) and park up near the three-mile marker.
If you want to get a drink before watching the action, you can head to Dial Arch, a lovely pub located in an old munitions building near the river. You won't have direct views of the marathon from the pub, but it's an easy two-minute walk to the route.
Looking more like a country village than the centre of one of the world's biggest cities, the centre of Greenwich is a beautiful - if crowded - spot from which to watch the marathon.
In 2018, the Cutty Sark opened up its main deck to spectators watching the race for the first time; while it's yet to be confirmed whether the same will happen for the 2019 London Marathon, it certainly makes for a unique view.
Alternatively, you could head to a pub nearby like the Gipsy Moth, which is right next to the Cutty Sark ship, or Old Brewery, which is also close. Again, it's going to be very crowded, so get there early!
Greenwich Union and Mitre Greenwich are also nearby the action, without being front and centre, so you might have a better chance of finding a spot there.
Next big stop on the route after Greenwich is Tower Bridge, running via Rotherhithe and Bermondsey to get there. Finally they'll turn the corner onto Tower Bridge, one of the most iconic views in London and one the most important milestones on the entire course.
Well-known for being the loudest spot on the course on marathon day, it's also one of the most popular places for spectators to gather as they cheer on the runners from the sidelines.
Officially, Virgin discourages people from nabbing a spot here because it gets so packed. But if you're tall enough to see over the crowds and you don't mind feeling like a sardine, it really is an exciting place to set up camp for the marathon.
Once they reach the north end of Tower Bridge, the runners will speed past the famous Tower of London to their left before turning right and hitting the halfway mark.
Even with the jubilant crowd, do spare a thought for the runners just coming over the bridge here as they catch a glimpse of all the speedier runners charging a full nine miles ahead of them!
Miles 13 to 22 consist of a loop around the Isle of Dogs and Canary Wharf, the financial centre of London. This stretch of the run is all canals, docklands and skyscrapers, giving runners a grand tour of the modern daily life of London workers.
Canary Wharf is where all the major banks and UK firms are based, but there's also a shopping centre and plenty of bars and restaurants around to entertain visitors from all walks of life.
Carrying on south from Canary Wharf, the London Marathon route winds its way to Mudchute, at the southern tip of the Isle of Dogs. This underrated section of London is quiet, picturesque and a great place from which to watch the race.
Plus, with less spectators around your cheers will make all the more difference to those taking part.
Mudchute Park and Farm is a large urban nature reserve that's home to dozens of animals, from chickens and ducks to llamas and pigs. Mudchute Park is a fantastic place to visit if you're exploring London with kids.
Plus, its unique setting - with the glittering buildings of Canary Wharf contrasting against the green grass of the farm - is unforgettable. If you're bringing children along with you to watch the race, you might want to choose this place as your base.
The London Marathon route then turns back north after passing the Mudchute Farm and loops around Poplar, All Saints and Westferry stations before passing St Katharine Docks.
This area, which was opened in 1828, was once one of the main commercial areas of the city. It was badly damaged during World War II and closed down for years before being redeveloped in the 1990s.
These days, the St Katharine Docks are home to flats, offices, and many restaurants and shops. There's also a World Food Market that takes place here every Friday.
Just before mile 23, the route passes Tower Bridge and the Tower of London once more before continuing westward, onto the homestretch.
As we've mentioned, you can join the throngs on Tower Bridge itself for a thrilling, albeit super crowded, vantage point. If you'd rather something a little less up-front, there are a number of pubs and restaurants nearby.
The Bridge House and Draft House pubs are both on the south end of Tower Bridge Road and should provide pretty good views of the race. With race-tracking allowing you to see how your friend or loved one is getting on, you can pop outside just in time for their arrival.
You could also park up at a spot by the River Thames just east of the bridge. You might not have great views, but the atmosphere will definitely be buzzing and you'll be within easy earshot of all the cheering!
Get in touch with nature and find a spot on Mudchute Park to watch the race. This is especially ideal if you're bringing along kids, as you can take a picnic and make a day of it. Plus, you can spend some time with all the animals in the farm once the runners have passed by.
There are also a few cafes and restaurants nearby to make your base. Mudchute Kitchen, right on the farm, opens at 9am and serves up tasty homemade breakfasts and hearty sandwiches. The easiest route to Mudchute Kitchen is via the Island Gardens DLR.
There are a couple of bars and pubs in Canary Wharf that are ideal for watching the race.
You can grab a drink at The Parlour, a bar in the Park Pavilion, which is right near where the runners will pass by. The seating with a view at The Parlour gets booked up super quickly, so call well in advance to claim a spot.
Westferry is a prime marathon-watching location because it's part of the loop, so you'll actually get to watch the runners go by twice.
Find a clearing on Westferry Road and bring some snacks and water to sustain you while you wait for the race to pass by.
Finally - the homestretch! It's this section that contains the most famous landmarks in London, making the London Marathon a truly iconic tour of the city.
After passing the Tower of London, the marathon runners will race along the Embankment towards their final destination. Along the way, they'll pass the distinctive St Paul's Cathedral to the right, one of the most popular attractions in London and definitely worth a visit.
Running past the Millennium Bridge, Blackfriars Bridge and Waterloo Bridge, the marathoners will end up along the Embankment, taking in some of the most recognisable structures in the city.
Across the river they'll spot the London Eye, the huge Ferris wheel that was unveiled in 1999 as part of London's Millennium celebrations.
On the north bank of the river, the runners will zip past the Palace of Westminster and the Big Ben clock tower, which is currently covered in scaffolding as it undergoes maintenance and refurbishment.
Going past Westminster Cathedral on the right and the Houses of Parliament on the left, the route continues on towards St James's Park in the City of Westminster.
Whether you're a photographer, a history buff or a nature lover, St James's Park is a must-see when you're visiting London. It's dotted with cafes and coffee shops as well as colourful flower beds and wildlife. Deckchairs along the park are the perfect stop for tourists who want to rest their weary feet.
St James's Park will be the final destination for the London Marathon runners, but first they must turn the corner around the west side of the park and race down the most important street in all of London: The Mall.
This broad, one-kilometre-long thoroughfare, which is painted red to look like a red carpet, is an official royal road used for parades, royal processions and nation celebrations.
Flanked by Union Jack flags on either side, and with Buckingham Palace perched right at the end of it, it's a marvellously British way to conclude the marathon.
After the runners cross the finish line in front of Buckingham Palace, many will walk across the road to St James's Park to meet their friends and family, relax, re-hydrate, and bask in the glory of finishing one of the most famous races in the world.
Expect to see lots of food, drink and celebration.
The area along the River Thames on the Embankment will be seriously packed, especially as you get closer to the finish line. Still, it's a pretty exciting and lively area to choose as your vantage point for watching the 2019 London Marathon.
We recommend finding a place between Embankment and Temple to witness the final lap.
You could also set up camp in The Blackfriar, a pub on Queen Victoria Street that's near to mile 24 on the route and has outdoor seating.
If you don't mind big crowds and waiting around for the end of the race, set your sights on The Mall. Here, you'll see all the grand finales and be able to witness the relief on the runners' faces as they finish the competition.
Although you won't be allowed into the secure finishers area, there is a designated runner meet and greet area in Horse Guards Road and Horse Guards Parade, where you can be reunited with your new running hero.
Bring a blanket and snacks so you can celebrate afterwards with everyone else in St James's Park.
Again, there are quite a few pub options around if you want to celebrate in true British style. Try heading to the Buckingham Arms, a traditional English pub just around the corner from Buckingham Palace.
The 39th annual London Marathon is going to be quite the event, with elite athletes like Mo Farah and last year's winners Eliud Kipchoge and Vivian Cheruiyot joining in.
Keep an eye on travel updates if you're planning on watching the race, and be sure to bring water and to keep your wits about you as you navigate the crowds.
If you need any more info, visit the official marathon website at virginmoneylondonmarathon.com.