The River Exe, with Exeter Cathedral in the distance
The River Exe is more than 50 miles long and stretches almost all the way from the Bristol Channel in the north to the English Channel in the south.
The source of the Exe is near Simonsbath on Exmoor - and it reaches the sea at Exmouth.
En route, it passes through many communities, including Tiverton and, of course, Devon's county town, Exeter.
The river has played an important role in the history and development of the east Devon area.
For example, the Romans reached Exeter in 50AD and turned it into a stronghold because this was the lowest point where the river could be crossed.
Over the centuries, Exeter developed as an important trading port and the quay was the hub of the city.
However, legend has it that the Countess of Devon threw a strop in the 13th century, having fallen out with the port of Exeter.
According to the tale (completely unproven), she built a weir, thus preventing big boats from reaching the city, which was why the Exeter Canal was built in 1566 - making it England's oldest ship canal.
The Exe at Topsham, which was a thriving port
It was built so that boats could again navigate their way to Exeter Quay from Turf Lock, where it rejoins the River Exe.
During this era, Topsham was also an important port.
Further up the river, the Exe also helped with the development of Tiverton, where water power was used for the booming wool industry.
The Exe has caused some major flooding in its time, regularly bursting its banks.
Some of the floods proved devastating, destroying churches and other buildings in Exeter, and wreaking havoc in other towns such as Tiverton and across farmland.
Flooding remains a problem along some stretches of the river, but a flood defence scheme built in Exeter in the 1970s has prevented major incidents in the city.
Where the river reaches the sea, there are important nature sites on each side of the estuary - at Exmouth and Dawlish Warren.
A bird-lover's paradise
Exmouth has a local nature reserve and Dawlish Warren is a national reserve as a result of the birdlife attracted by the estuary habitat. The entire estuary is a site of special scientific interest (SSSI).
The Exe Estuary, viewed from Dawlish Warren
Many species flock to the area, including avocet, curlew, teal, Brent geese, oystercatchers, dunlin, redshank, grey plover, and godwits.
At the right times of the year, the estuary is a birdwatcher's paradise.
All the way along the Exe there are places to canoe, and the river these days is important to the holiday and leisure industry.
It's traditionally been a favourite place for anglers, and in 1924, a salmon weighing 64lb was caught by fisherman Richard Voysey. It became known as the famous Exe Salmon.
Because of the decline in salmon populations in Devon's rivers - including the Exe - the relevant authorities launched an action plan to reverse the decline. But it's unlikely we'll ever see another 64-pounder.
The Exe's other role is providing water for Wimbleball Reservoir on Exmoor.
Up here on the moor, the Exe passes through wet moorland, woodland and steep-sided valleys, in an environment which is a complete contrast to that found at the other end of the river.