By Stephen Dowling BBC News Online entertainment staff

The festival attracts music fans from all over northern Europe

Roskilde Festival - which opens on 1 July - is not only Denmark's biggest rock event, but one of the biggest festivals in Europe.

In 2000, the festival, a four-day-long celebration of music in the city of the Danes' ancient kings, hit the headlines for all the wrong reasons.

Pearl Jam's Saturday night headlining set was the focal point for a tragic turn of events.

Waterlogged ground, low sound levels and many drunken revellers in the 50,000 crowd led to a stampede towards the stage that killed nine people.

Criticism

Roskilde, which had quietly been drawing rock fans from all over Europe for the past three decades, suddenly had the full glare of world attention.

Several major bands due to play the following day, including Oasis and the Pet Shop Boys, pulled out over safety concerns.

The festival, which was ruled to have had no responsibility for the deaths of the fans by Danish police, has since fought to regain its reputation as one of Europe's most popular music events.

Roskilde started in 1971. It is based on an agricultural and cattle show ground site, but it differs from the UK's Glastonbury in that it is held on a dedicated site and not a farm.

It is just over half an hour away from the centre of Copenhagen via train, a far cry from the more secluded - some would say "difficult to get to" - Glastonbury. There are even direct trains from Copenhagen's Kastrup airport.

Bob Dylan is one of the acts to have headlined Roskilde

Roskilde receives some of its funding from the Danish government, and compared to the sometimes overly-commercialised nature of British festivals, seems to retain an un-commercial edge.

Fans can camp four days before the festival actually starts, and the sight of Danish, German and Norwegian fans dragging crates of beer behind them at the festival gates is part of the Roskilde tradition.

While Roskilde does not fill its timetable with as many bands as Glastonbury, its menu is consistently as eclectic.

This being liberal, internationalist Scandinavia, world music is an important part of the musical smorgasbord as more mainstream acts.

Volunteers

The festival attracts the very top acts too. In recent years REM, Metallica, Neil Young, Bob Dylan, Travis and the Beastie Boys have all played at Roskilde.

British band Suede, who are huge stars in Denmark, played three separate sets there in 1999, playing on the main stage and on two of the smaller tents with a range of material.

Roskilde regularly attracts 90,000 fans - of these 20,000 are volunteers who get free access to the festival in exchange for working as cleanup crews for part of the time.

While this is a good 30,000 less than the official Glastonbury figure, Roskilde often features many of the same headliners.

Glastonbury organiser Michael Eavis often works with the Danes to offer slots at both festivals for some of the bigger acts, therefore making it worthwhile for bigger acts to play Europe.

Roskilde often acts as the Danish leg for many major world tours.

Audience members were shocked by the deaths in 2000

Roskilde, like Glastonbury, promotes environmental and peaceful causes. The festival's own website says it pledges to use environmentally-friendly products as much as possible, and that it must do the utmost to recycle waste.

Festivalgoers used to the detritus of the average British rock festival might be pleasantly surprised with the state of Roskilde - the 20,000 volunteers are responsible for clearing the site of as much rubbish and food waste as possible.

And fans play their bit too - plastic glasses returned to the beer tents mean a discount on the price of the next pint.

David Bowie, the Pixies, Morrissey and Franz Ferdinand are among acts on the line-up for this year's show.

While it may lack the pastoral atmosphere that attracts many to Glastonbury, Roskilde looks set to remain amongst the biggest events in Europe's musical calendar.