Why do people celebrate Bloomsday?

On one day every June, the streets of Dublin are transformed to a bygone era.

People are dressed in straw hats tied with ribbon and Edwardian outfits.

It's 16 June, Bloomsday, or the day on which James Joyce set his great literary work, Ulysses.

Joyce fans admit it is a "big book", spanning 700 pages in length with more than 265,000 words.

Those who makes it through from start to finish will be treated to a snapshot of Joyce's Dublin, with the story taking place in different locations around the city, all based on real places.

There's Sweny's Pharmacy on Lincoln Place, now a book shop, and on Duke Street stands Davy Byrne's pub, still in business more than 100 years later.

For Joyce fans, Bloomsday is an opportunity to step into the novel.

Each year they dress up, some as characters from the book, others in outfits inspired by the era, and they move around each location recreating and reciting scenes from the book.

Most Bloomsday enthusiasts can be spotted from afar, as they wear straw hats donned with ribbon.

Michelle O'Toole made her own dress and brought along her daughter Amelie O'Toole Driuex for her first Bloomsday.

"My dress is actually made of an old curtain that I've had for years," she explained.

"I cut it into pieces, and have sewn it all together.

"Even the lace detail is actually a net curtain. The hat I had and I attached some flowers to match my dress and I had this parasol anyway that i wore one year to the races."

Outside Davy Byrne's pub on Duke Street, straw hats were being handed out.

Many men were dressed in three piece suits and bowties, while women wore elaborate hats with large colourful flowers and long dresses in bright and bold colours.

Jennifer Whelan and Claire Devlin said they read the "big book" in a book club over nine months.

"It changes the whole experience of living in Dublin because now I walk around and I think, oh, 'Bloom did that there' and 'that's where he ate'," said Devlin.

"It feels so real and if you dress up and get really involved in the festivities, it feels even more real - and also people are really nice to you if you're wearing the hat."

Whelan explained how they embellished the hats themselves, using chicken wire to attach large white and red roses.

Bloomsday is an annual literary celebration held on 16 June every year to mark the life and work of author James Joyce.

The day is named after Leopold Bloom, one of the protagonists in Joyce's 1922 novel Ulysses.

The exact date of Bloomsday's origins is unclear.

Festival organisers note a letter sent by Joyce to a friend in 1924, two years after the book was first published, in which he wrote "there is a group of people who observe what they call Bloom's day".

The novel takes place entirely on a single day - 16 June 1904.

Andrew Basquille, a volunteer with the Joyce Tower and Museum in Sandycove, said Joyce had a personal reason for choosing this particular date.

"The reason that Joyce set it on that date is because that is the date that he had his first date with Nora Barnacle, who eventually became his wife.

"So all over the city, people have readings, songs associated with the book, reenactments of various episodes."

Basquille is at Glasnevin Cemetery for a reenactment of the funeral for the fictional Paddy Dignam, which is attended by Joyce's protagonist Leopold Bloom in Ulysses.

The cemetery has more than one million people buried in it, including Irish revolutionary leaders Michael Collins, Arthur Griffith and Countess Constance Markievicz, who played key roles in constructing the Irish State.

Blaise Reid, who took part in the re-enactment, said he has been reading the book for several decades.

"I was given Ulysses for my 21st birthday and I am now 54 and still working through it," he said.

"It's an incredible read and it's very complicated in a lot of ways."