- G7 summits
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US President Joe Biden has arrived in the UK for his first official overseas trip.
It is his first stop on an eight-day visit to Europe. He will attend a G7 leaders' meeting in Cornwall and see the Queen before crossing the Channel for more official events – including his first Nato summit as president, and concluding by meeting Russian President Vladimir Putin in Geneva.
Mr Biden does not travel lightly. The US president has an array of specialty vehicles to help him move around in safety and comfort, on land and in the air.
And none is more iconic than the presidential plane – Air Force One.
The aircraft landed at RAF Mildenhall in Suffolk on Wednesday, where Mr Biden met with US personnel stationed at the base before flying to Cornwall.
As the White House website explains, Air Force One is actually the air traffic control sign for any Air Force aircraft with the US president on board.
But for the most part the term is used to refer to the two famous white and blue planes – specially adapted Boeing 747-200B series aircraft, which carry the tail codes 28000 and 29000.
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The planes have advanced communications, avionics and defences – including protection against electromagnetic pulses and flares to throw off heat-seeking missiles – which mean they can function as an airborne, mobile command centre in case of an attack on the US.
They are also capable of refuelling in the air, meaning in theory the planes have unlimited range.
Inside, there is 4,000 sq feet (372 sq m) of floor space spread over three levels. Aside from a presidential suite, there are also medical facilities, food galleys, and space for advisers, Secret Service protection officers and journalists.
For short trips in the air, the president uses helicopters – recognisable by their predominantly green body and white top.
Marine One – again, not just one helicopter, but the name for any Marine Corps aircraft carrying the US president – usually refers to a VH-3D Sea King or a VH-60N White Hawk.
Decoy versions of Marine One often fly alongside the president's helicopter. It is also usually accompanied in the air by escort aircraft, including the Osprey MV-22 – known as a "Green Top".
UK readers may remember the tilt-rotor aircraft flying over London during former President Donald Trump's visit in 2018. They are capable of vertical take off and landing, and are designed to combine the functions of a helicopter with the range of a turboprop aircraft.
Once on the ground, President Biden transfers from Air Force One or Marine One to Cadillac One – nicknamed The Beast.
This generation of presidential car debuted in 2018.
Manufacturer General Motors and the Secret Service have not given much away about the car's specific security features. But reports suggest it weighs about nine tonnes (20,000lb), and has an armour-plated body and bulletproof windows.
It reportedly has tear gas grenade launchers, night vision cameras and a built-in satellite phone. The passenger cabin is said to be sealed, and the tyres are reinforced so the car can still move even with flat tyres.
The Beast can hold at least seven people and has a wide range of medical supplies on board, including a fridge with blood matching the president's blood type, in case of an emergency.
A large procession of vehicles – consisting of security, medics, aides and the press – is also part of the presidential motorcade.
Secret Service agents will have already travelled to Cornwall to scout out the location of the G7 summit – looking for the best route through the narrow country lanes for The Beast and its entourage.
Former President Barack Obama's visit to Downing Street in 2009 became a viral hit after the car struggled to turn in the famous street. The driver on another trip in 2016 was more successful.
Access is strictly controlled to Carbis Bay on the north coast of the county, where global leaders are gathering for the event.
The world's seven largest co-called advanced economies take part in G7 summits. Aside from the US, this includes Canada, France, Germany, Italy, Japan, the UK and the EU.