Why food scraps are 'the most important type of rubbish'
My Perfect City
Four reasons to recycle your food waste
The green city: San Francisco, USA
Is San Francisco’s recycling scheme and sustainable public transport a model to follow?
The smart city: Seoul, South Korea
How is data being used to help Seoul run smoothly?
The 24-hour city: London, UK
How the UK capital makes money around the clock
Participatory budgeting: Paris, France
In Paris citizens vote on how to spend the city’s budget. Is this a model to follow?
Knife crime: Glasgow, Scotland
How Glasgow, which has one of the highest murder rates in Europe, is tackling knife crime
Medellin, Colombia: Slums and urban regeneration
The visionary project that transformed the violent barrios of Colombia's second city
Lancashire outdoors: An ecological county tour looking at issues of farming and food.
The RHS Chelsea Flower Show Special
Rebecca Parker reflects the breadth of local horticultural talent at Chelsea.
The Sunday Omnibus - Art, Sexuality and Faith
Fi Glover with the omnibus edition of three conversations about art, sexuality and faith.
Colum Arbuckle shares the life stories of older people in Northern Ireland.
Your gardening calls answered with Jonathan Ray and our gardening expert Reg Moule.