The Blackwater in Essex, which rises near Saffron Walden, has a course of about 40 m.
The country around is flat and fertile, producing much wine, dates, oranges, oil, saffron and aniseed.
Saffron was used as an ingredient in many of the complicated medicines of early times.
Saffron is grown and exported.
Next, via country lanes to saffron Waldon, a village once famed for growing saffron.