It is 10 years since the first bikes belonging to London's cycle scheme were used on the streets of the capital.
A decade on, BBC News takes a look behind the handlebars.
The scheme's origins
While the cycles are still known by many as "Boris Bikes", it was Mr Johnson's predecessor Ken Livingstone who set up a feasibility study into the creation of a cycle hire scheme in London, having been inspired by one in Paris.
The scheme was launched by Mr Johnson on 30 July 2010, when he announced that he wanted the city to be "filled with thousands of gleaming machines", which would "become as commonplace on our roads as black cabs and red buses".
Ninety-three million hires
Since their launch, the bikes had been hired an impressive 93,299,451 times by 30 June this year, according to figures from Transport for London (TfL).
On 9 July 2015 when the entire Tube network was closed because of a strike, bikes were hired 73,094 times, making it the busiest day since the scheme began.
The day which had the fewest hires was 19 December 2010 with just 2,764. Presumably it was cold and miserable that day.
Celebs in the saddle
The occasional famous face has been spotted using one to get around the capital. For some it may have been a photo opportunity, but for others they were just a convenient mode of transport.
Actor, bodybuilder and former politician Arnold Schwarzenegger joined then-mayor Mr Johnson for a trundle in March 2011, then went solo for another trip around the capital in June 2015.
The comedian Russell Brand made use of one of the bikes during an anti-austerity protest in Westminster in June 2014.
And slightly more randomly, movie baddie the Predator was pictured cycling across Westminster Bridge. Perhaps it was searching for Arnie.
The scheme expands
When the scheme began there were 350 docking stations and 5,000 bicycles.
These days there are 781 docking stations and, with another 1,700 new cycles set to join the ranks, there will soon be more than 14,000 of them on the streets.
The scheme now covers 100 sq km (38.6 sq miles) of London, making it one of the largest cycle hire schemes in Europe.
The mechanics behind the machines
The sturdy aluminium bikes have three-speed gears, a bell and a basket.
Of the bikes first rolled out 10 years ago, 3,993 are still on the road today, although their parts will have been replaced to ensure they are safe and working well.
A total of 6,654 cycles have been decommissioned since the scheme began because of reasons such as they've been lost, stolen or damaged beyond repair.
How to ride
The scheme works by users taking a bike from a docking station and then being able to leave it at any of those in the capital - assuming there is a space free.
Initially, only signed up members who paid an annual fee and had a fob which was sent to them through the post could hire the bikes.
The technology soon changed and while yearly membership is still available, users are also able to just turn up at a docking station or use the official app to hire bikes.
Barclays initially sponsored the scheme, which was worth £5m a year and led to the bikes being given their original blue livery.
In February 2015, it was announced that Santander would take over sponsorship and the following year the bikes became red. It also meant they gained their current official name - Santander Cycles.
Back in 2010, people paid an annual fee of £45 to be a member along with a usage charge if a bike was taken out for more than 30 minutes. For up to an hour it cost £1, 90 minutes cost £4, and 24 hours cost £50.
Annual membership these days costs £90 a year. Journeys less than 30 minutes long are still not paid for but it costs £2 for every 30 minutes after that.
Those using hire and ride without membership pay £2, which allows them to make an unlimited number of journeys of up to 30 minutes within a 24-hour period. Journeys that take longer than 30 minutes cost £2 for each extra 30 minutes.
The pandemic effect
There has been a huge increase in the number of people using the bikes over the past few months.
May saw the busiest week in the scheme's history, with 363,000 hires made between the 25th and 31st of that month.
Cycles have been hired more 50,000 times in a day on 10 occasions in the past two months. Over the decade before this year, that had only happened twice.
A very long trip
In September 2015, Bournemouth-based Baz Bignall rode a London cycle scheme bike from John O'Groats to Land's End for charity.
Fortunately, TfL didn't charge him for the hire.