Ciaran Hinds introduces a series of letters written 100 years ago by Titanic passengers.
BBC Radio Ulster
Melvyn Bragg and his guests discuss the emergence of geology as a scientific discipline.
BBC Radio 4
Presented by Tom Holland. Marking the centenary of the sinking of the Titanic.
Matthew Sweet tracks a Native American movie-maker from California to the London of 1914.
BBC Radio 3
Jonathan Coffey on the story of the cross and how it became the symbol of Christianity.
Melvyn Bragg and his guests discuss the origins of Quakerism.