Strange sculptural objects

At the Natural History Museum on a rainy Sunday, amid the hordes of families queuing to see the dinosaurs, these objects in an alcove caught my eye -They're wasp nests made by three different species in Brazil. Here's a closeup -
Local wasp nests aren't so grand, but do have an interesting structure. On the isle of Skye, wasps build their nests in the heather, as shown here.

Of course wasps can be a pest in late summer, but nests should be left undisturbed - the entire colony will die out in the autumn and the queen will go into hibernation. Then the nest can be removed.