The main celebrations for Sant Joan in Barcelona take place on the evening of June 23rd before the public holiday on June 24th on what is known as the Revetlla de Sant Joan in Catalan and the Verbena de San Juan in Spanish.
Saint John's Eve roughly corresponds to the Summer Solstice or Midsummers' Eve in English, the longest day of the year.
Interestingly, in Spain, Sant Joan marks the beginning of summer rather than the middle and also heralds the start of the school holidays so not surprisingly is very popular with children.
The Feast of Sant Joan is celebrated mainly throughout the Catalan-speaking countries of Catalonia, Valencia, the Balearic Islands and the French Province of Rousillon, which is known as Rosselló in Catalan or more simply Catalunya Nord, or North Catalonia, because it was Catalan territory until the 1650s.
As capital of the Països Catalans or Catalan Countries, the Sant Joan celebrations in Barcelona are particularly wild and are also loaded with Catalan national significance.
Also known as the Nit de Foc or Night of Fire, with its fireworks and bonfires Sant Joan in Barcelona is like a bit like Guy Fawkes' Night held in summer on the shores of the Mediterranean so I'm sure you can imagine that it is a great deal of fun.
As Sant Joan on 23rd June almost coincides with the Summer Solstice normally on 20th or 21st June, it is likely that the the origins of the festival are pagan.
Similarly the importance of fire, witches and herbal remedies in the traditional celebrations suggest that Sant Joan is a pre-Christian festival that has been hijacked by the church to coincide with the birth of Saint John.
It has also been said that the festival is so debauched because it occurs at the furthest part of the year from the birth of Christ.
The building of bonfires on the Summer Solstice is typical throughout Northern Europe but it is unclear when the tradition became associated with Sant Joan in Barcelona.
In Don Quixote, published in 1605 and 1615, Cervantes famously sets his hero's entry into Barcelona on the Eve of Sant Joan and makes no mention of bonfires or celebrations.
For this reason, it has been suggested that the Night of Fire is a modern invention.
However, Miguel de Cervantes was a natural of Alcalá de Henares near Madrid and may not have been fully aware of the typical festivals celebrated in Catalonia.
Furthermore, a Barcelona City Council edict dating from 1780 forbids the building of bonfires within the city limits so it seems very probable that the tradition of building bonfires for Sant Joan goes back at least to the 18th century.
The event loaded with most national significance during the Revetlla de Sant Joan in Barcelona is the arrival of the Flama de Canigó at the Parliament of Catalonia in Parc de la Ciutadella at 12.30.
The tradition of bringing a flame from the emblematic mountain of Canigó located in Catalunya Nord in the French Pyrenees is a very recent addition to the festival and definitely adds an important Catalanist element.
In 1955, inspired by the epic poem Canigó in which the great 19th century Catalan poet Jacint Verdaguer mentions fires on the peak of Canigó mountain for the Feast of Sant Joan, Francesc Pujades from Arles de Tec in Vallespir in Catalunya Nord decided to light a bonfire on top of the mountain and use the flame to light other fires in the region.
The tradition quickly spread throughout French Catalonia and in 1965 it was decided to install the flame at the Museu de la Casa Pairal in Castellet de Perpinyà and keep it it alight all year so the fire on Canigó could be relit on June 22nd.
In 1966, despite the Franco Regime, the flame crossed the border into Spain and was used to light the Sant Joan fires in Vic in Central Catalonia and since then the tradition has spread throughout Catalonia and even as far as parts of Valencia.
Today it is calculculated that the flame from the peak of Canigó is used to light over 3,000 bonfires throughout the Països Catalans.
In Barcelona, the flame is received with full honours at the Parliament of Catalonia at 12.30 and at 6 pm a procession begins in the District of Les Corts.
The main celebration, though, is when the flame arrives in Plaça de Sant Jaume at 7 pm and is greeted by Gegants, speeches and traditional dances and songs.
At 7.30, representatives from the different neighbourhoods light their own torches from the flame and the Flama de Canigó is then used to light the official bonfires throughout the city.
In the run up to the festival of Sant Joan, fireworks go on sale throughout the city with the very noisy petards, or bangers, being by far the most popular with adolescent boys and naughty middle-aged men, in particular.
Given the potential dangers inherent in the use of fireworks I strongly recommend that you purchase them from a recommended dealer.
Surprisingly, there is no official firework display organised by Barcelona City Council for Sant Joan.
There are official and unofficial fogueres or bonfires all over
Barcelona on the Nit de Sant Joan with possibly the most important one
being on the at La Barceloneta Beach.
The official starting time is 9 pm but as it is on the beach it tends to be very popular so if you want a good position it makes sense to get there a little earlier.
You'll find other Fogueres of interest all over the city and I would also recommend the celebrations at Passeig Lluís Companys next to Arc de Triomf metro station, which coincide with the Festa Major del Casc Antic.
You'll find revetlles or street parties in all of the Barcelona neighbourhoods.
These generally involve a Sopar Popular, which is a kind communal dinner where people sit at tressle tables.
Sometimes you have to bring your own food but the traditional Coca de Sant Joan cake will definitely be provided.
The picture shows Coca de Sant Joan, which is a doughy cake topped with candied fruit, sugar and sometimes pinenuts and is extremely tasty.
There is often a live band or a mobile disco and some revetlles may also have a small fire and firework display.
They tend to start late evening and go on until the early hours of the morning so it's almost impossible not to have fun.
As Sant Joan is one of Barcelona's major festivals, it will be difficult to avoid the festive atmosphere.
It's also worth remembering the public holiday is not until the following day so you will find many bars and restaurants open offering a Sant Joan menu and later on there will be Revetlla parties at many of Barcelona's clubs and discoteques.
Speaking personally, I generally celebrate the Revetlla de Sant Joan at a private house party with friends where there is always good food in abundance and the wine and cava flows freely.