A partly-underground house with a field for a roof will take on artist Damien Hirst's new London gallery in the competition for the UK's top architecture award.
The two buildings are among six shortlisted for the Royal Institute of British Architects (Riba) Stirling Prize 2016.
Also in the running for the award are two projects at Oxford University, a college in Glasgow and a housing estate in south London.
The underground Outhouse in the Forest of Dean, Gloucestershire, was designed by Loyn & Co Architects for two retired artists, and it is the first private house to feature on the prize shortlist for 15 years.
The architecture practice is nominated for the first time, as is Michael Laird Architects for designing the City of Glasgow College Riverside Campus with Reiach and Hall Architects.
The two Oxford projects shortlisted are the Blavatnik School of Government by Herzog & de Meuron and the restoration of the Bodleian's Weston Library by WilkinsonEyre.
Hirst's Newport Street Gallery is a free gallery housing his private collection, converted by Caruso St John Architects from three Victorian workshops previously used to create sets for West End productions and two other buildings.
The second London development shortlisted is the 235 homes at Trafalgar Place designed by dRMM Architects - the first whole-scale redevelopment of Elephant and Castle's 1970s Heygate Estate.
Riba president Jane Duncan said: "The Riba Stirling Prize is awarded to the building that has made the biggest contribution to the evolution of architecture in a given year.
"Every one of the six buildings shortlisted today illustrates the huge benefit that well-designed buildings can bring to people's lives."
The winner of the award, now in its 21st year, will be announced on October 6.