The Dengineers build 11-year-old Ben a camouflaged adventure bunker.

Sibling rockers Sami, 9, and Nadia, 12, need their own soundproofed rehearsal room.

A massive Manchester United fan, 10-year-old Billy is in need of a football den.

Ella wants a den to escape the 35 bikes that are kept in every room of the house.

Jazz and Katelyn love dancing and want to put a dance studio in Jazz's mum's cellar.

Eleven-year-old Nathan wants a kitchen hangout, where he can practise being a chef.

Nyobi needs room, a desk space and art materials, for her design projects.

Ten-year-old Ben wants a den with enough room for his beloved train set.

Sienna really needs a new bedroom which can double up as a spy den, with lots of gadgets.

The pupils of the Lancasterian School want an exciting space that everyone can hang out in.

The presenters look back at all the dens they have built throughout the series and reminisce about the great kids, the tense surprises and the big reveals.

The Dengineers transform a youth centre's outside space.

The Dengineers build 10-year-old Aron his very own Bollywood den.

The Dengineers come to the aid of Carrie, a 10-year-old from Leeds who plans to celebrate her red hair with a gingerbread house den.

The Dengineers build 11-year-old Lola an old-fashioned cinema den.

Needing to go to hospital means Rufus often misses out on the play adventures he loves.

The team build 11-year-old Joshua his very own DJ den and take a visit of the BBC Radio 1 studios.

The team build 11-year-old Whitney her very own den to answer all her eco needs.

The team build 11-year-old Phillip his own den where he can build model planes.

Eleanor, 10, loves books, so the team bring the library to her - a magical library!

The team create a fantastic journalism den where Soibi can write news reports.

The team look back at all the amazing dens built throughout the series.

The presenters look back at some of the amazing dens from series one and two. Here, Lauren revisits the survival, art, Hollywood cinema and DJ dens.

The presenters look back at some of the amazing dens from series one and two. Here, Lauren revisits the train, magical library, community and plane dens.

Helena needs a den to help her reach for the stars and fulfil her science dreams.