Sandi Toksvig meets David Winpenny, who has toured the British Isles looking at the surprising number of pyramids there are scattered around - from gravestones and memorials to follies, works of art and functional buildings. The pyramid is not only one of the most ancient of structural designs but one of the most modern, and all over the country people are proud of their local pyramids and welcome those who have travelled to see them.
Ruth Breckman's tour in search of buildings took her to five continents to see opera houses. Again these vary from the old, like the famous 18th-century La Scala in Milan, to the modern Marion Oliver McCaw Hall in Seattle. She explains why the opera house can tell the visitor so much about the history and culture of a city.
An object that travels all over the globe, often unnoticed but vital to the way the world works, is the shipping container. Jeremy Hillman explains how BBC News bought and tracked an individual container for a year, logging its travels, cargo and the crews who navigated its voyage. The journey tells us a lot about globalisation and gives a telling insight into the current state of the world's economy.