'Games wide open' is the motto for this year's Paris Olympics, which officially begin on Friday with the opening ceremony.

It is the first time in 100 years the French capital has hosted the summer Games, with the majority of the events taking place in or around the city's most iconic areas.

Friday's opening ceremony will feature boats carrying athletes and dignitaries down six kilometres of the River Seine, with room for 300,000 spectators.

Few details are known about the event - though there has been speculation about Celine Dion and Lady Gaga performing - with the ceremony's artistic director Thomas Jolly saying he wants to "show France in all its diversity".

The Paris Games is the first to achieve gender parity among athletes, with 5,250 male and 5,250 female athletes set to compete.

With millions expected to attend, Paris is making the final touches for a Games it hopes will be like no other.

French President Emmanuel Macron said earlier this week, external that the country was "ready and we will be ready throughout the Games".

However, some Parisians have used social media to warn people, external about issues such as overcrowding, price inflation and difficulties in getting around the city.

On Friday, hours before the opening ceremony began, a series of fires badly affected the French rail network, with the Eurostar also impacted.

There is a huge security operation in place, with up to 5,000 police, soldiers and hired guards on patrol at any one time. The Seine - the river than runs through the centre of Paris - has been fenced off for the opening ceremony, leaving residents needing QR codes to access certain areas.

That has affected local businesses along the Seine, leading to some criticism,, external but French authorities say the barricades will be removed after Friday's event.

The cost of this year's Games is expected to be about 9bn euros (£7.6bn), with the organising committee promising to make it the greenest Olympics in history.

Only two arenas are new and purpose-built - an aquatics centre and an arena for badminton and rhythmic gymnastics.

Other iconic venues such as the Stade de France - the national stadium - and French Open tennis venue Roland Garros will host events, alongside historic sites such as the Grand Palais and the Place de la Concorde.

One of the big concerns in the build-up was the water quality of the Seine, which will host the swimming leg of the triathlon and open-water events.

Swimming in the river was banned for a century because of the water quality, with tests in June still showing levels of E.coli above the upper limits imposed by sports federations.

However, Paris mayor Anne Hidalgo swam in the river on 17 July to try to prove it was safe.

The water will be tested regularly in different areas before the events.