This helicopter footage shows how far floodwater from the River Danube has engulfed the historic town of Melk in northern Austria.
The town's famous Benedictine abbey can be seen safely out of touch on its hill, but the old town all around is partly submerged.
More top news
The band announced at a free concert on Friday that they would take over the event's Pyramid stage on Saturday June 25.
The victims were collecting permits and escorts a day after their home town was liberated from the extremists.
Scotland Yard said the male youths will appear in custody at Westminster Magistrates' Court on Saturday.