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Thames Head -

Before you cast off, here's a bit of background. Debate surrounds the exact location of the source of the River Thames. Many insist the river rises at Thames Head near Kemble parish church in the county of Gloucestershire. Pictured after heavy rainfall is the marker stone where the Thames is believed to bubble up as spring water. (Photo: Wikimedia/CC BY-SA 4.0)

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Seven Springs -

However, Seven Springs near Cheltenham, also in Gloucestershire, is also sometimes quoted as the Thames' source, above which a plaque reads in Latin: "Hic tuus o Tamesine Pater septemgeminus fons" ("Here, O Father Thames, [is] your sevenfold spring"). (Photo: Wikimedia/CC BY-SA 4.0)

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Oxford -

The Thames flows through Oxford, where it is known locally as the River Isis. The city is home to the University of Oxford, the oldest university in the English-speaking world, and one of the most esteemed. Here, the Thames meets the River Cherwell. Both provide pleasant sightseeing cruise options. In summer, boating is very popular.

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Henley-on-Thames -

Further east and still in Oxfordshire lies Henley-on-Thames. Noted for its collection of historic structures and buildings, including a bridge dating back to 1786, Henley is world-renowned as a center for rowing. Each summer the Henley Royal Regatta is held on a stretch of the Thames just north of the town center.

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Windsor -

From Oxfordshire, the Thames meanders into Berkshire and past Windsor. From the river, Windsor Castle is clearly visible in all its grandeur. The original castle was built in the 11th century to oversee a strategically important section of the Thames. Today the preferred weekend home of Queen Elizabeth II, the castle and its grounds draw visitors from all over the world.

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Twickenham -

Twickenham is famous as the home of rugby union in England. The town, part of the London Borough of Richmond upon Thames, is bordered on the southeastern side by the River Thames and Eel Pie Island, which has about 50 homes and nature reserves at both ends. It low banks provide privileged mooring facilities for houseboats. (Photo: Wikimedia/CC BY-SA 4.0)

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Richmond -

The ever-widening river continues slowly east to meet Richmond, known for its splendid Georgian architecture, inviting riverside pubs and restaurants, and several parks and open spaces including Richmond Park.

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Islands of the River Thames -

Incidentally, did you know that there are almost 200 islands on the Thames? Passing Richmond you'll see another one of them, Glover's Island, pictured here from Richmond Hill.

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Hampton Court Palace -

Richmond upon Thames also regales sightseers with one of England's most majestic buildings, Hampton Court Palace. Just 19 km (12 mi) upstream from central London, this 16th-century treasure, once the favored residence of King Henry VIII, is set near the river and has often served as a location for film and television productions. 

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Hammersmith Bridge -

After Richmond the river approaches west London and Hammersmith, which forms part of the north bank of the Thames. Here you pass under Hammersmith Bridge. The current structure dates back to 1887 and is recognized for its wrought iron suspension cables. In fact, one of the great joys of a River Thames cruise is gliding under the many bridges that span the waterway. (Photo: Flickr/CC BY-SA 2.0)

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Albert Bridge -

One of London's most attractive bridges, Albert Bridge dates back to 1873. Little used by traffic, the bridge is illuminated at night by 4,000 LEDs adding to its status as a very visible landmark. (Photo: Wikimedia/CC BY-SA 3.0)

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Chelsea Bridge -

After passing under Albert Bridge, the next bridge you'll meet is Chelsea Bridge. Opened in 1937, this is another London bridge that's especially noted for its illuminations. (Photo: Wikimedia/CC BY-SA 3.0)

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Battersea Power Station -

Battersea Power Station has stood as a  defining London landmark since the late 1920s. Now redeveloped as a commercial and residential complex, the power station's four iconic chimney stacks remain a cherished feature of the London skyline. (Photo: Flickr/CC BY 2.0)

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SIS Building -

Next up is the headquarters of the Secret Intelligence Service (SIS, MI6). Inaugurated in 1994, the building, the address of which is Vauxhall Cross, has appeared in several James Bond movies, most famously perhaps in 'The World is Not Enough' (1999), when is was very realistically depicted as having been attacked.

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Palace of Westminster -

Hopefully neither shaken or stirred, your voyage continues. Coming into view after rounding a bend further downstream is the Palace of Westminster, one of the most recognized landmarks in the world. Informally known as the Houses of Parliament, the palace dates back to 1876 after the original medieval building was destroyed by fire in 1834. The Elizabeth Tower (currently shrouded in scaffolding due to ongoing refurbishment) houses Big Ben, the nickname for the Great Bell, the chimes of which are familiar to millions around the globe.

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London Eye -

Set on the south bank a little further on from the Palace of Westminster is the huge London Eye, or the Millennium Wheel. This is the most popular paid tourist attraction in the United Kingdom with over three million visitors annually. The views from the capsules are simply breathtaking.

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St Paul's Cathedral -

By now you're sailing through the vibrant and pulsating heart of one of the most celebrated capital cities on the planet. As you pass under the pedestrian Millennium Bridge, gaze over to your left and feast your eyes on St Paul's Cathedral. Its dome has dominated the London skyline for over 300 years.

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Tate Modern -

St Paul's is a scene-stealer, but don't forget to look in the opposite direction for a glimpse of the Tate Modern. This is Britain's national gallery of international modern art and is housed in the former Bankside Power Station.

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City of London -

The City of London, colloquially known as the Square Mile, is London's financial center. Here you're greeted by a forest of steel and glass, a collection of soaring contemporary structures that include the "The Gherkin" and "The Walkie-Talkie." Wikimedia/CC BY-SA 4.0)

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The Shard -

You can't miss The Shard. Standing 309 m (1,016 ft) on the opposite bank of the Thames facing the City of London, this is the United Kingdom's tallest building. Impressive at any time of day, it's especially alluring at dusk when illuminated, as is all the Square Mile.

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Tower Bridge -

Lying almost in the Shard's shadow is Tower Bridge. A combined bascule (moveable) and suspension bridge, this is another one of the capital's favorite landmarks. If you're sailing on a two- or three-tiered sightseeing boat, they'll raise the drawbridge for you. A real treat!

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Tower of London -

Tower Bridge lies within sight of the Tower of London, on the north bank of the River Thames. From the river you can clearly see the entrance to the infamous Traitor's Gate (pictured bottom center). Back in the day, those led through here rarely greeted the next day.

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HMS Belfast -

Permanently moored near Tower Bridge is HMS Belfast, a light cruiser that saw action during World War II. It's now a museum ship and is operated by the Imperial War Museum.

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Canary Wharf -

Your sightseeing cruise is now taking you beyond central London and towards Docklands. The docks were formerly part of the Port of London. The centerpiece redevelopment is Canary Wharf.

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St Katharine Docks -

Lying on the north bank of the River Thames is St Katharine Docks, once one of the commercial docks that made up the Port of London. Today it's an upmarket housing and leisure complex.

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O2 Arena -

One of the United Kingdom's principal entertainment venues, the O2 Arena is a multipurpose indoor arena that's hosted numerous music concerts, sports tournaments, and comedy shows.

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Greenwich Park -

As the boat slips further east, the Thames gives up another charming gem: Greenwich Park. The green space, a former hunting park, commands fine views over the river,  the Isle of Dogs, and the City of London.

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Greenwich Observatory -

Greenwich is also the location of the renowned National Maritime Museum and the Royal Observatory. The prime meridian passes through this revered building, and gives its name to Greenwich Mean Time.

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Thames Barrier -

The Thames Barrier marks the end of your voyage. This state-of-the-art moveable barrier system is designed to prevent the floodplain of most of Greater London from being flooded by exceptionally high tides and storm surges moving up from the North Sea. Up to June 2020, a total of 193 flood defense closures had been recorded.

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Thames Estuary -

Beyond the Thames Barrier, the River Thames widens into a vast estuary. It constitutes a major shipping route, serving as it does as a gateway to the North Sea.

See also: The world's most insane white water rafting destinations.

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