Some are not just useful, they're beautiful and historic.
Many settlements grew up close to rivers, with important bridges or other crossings nearby.
The expression 'we'll cross that bridge when we come to it' probably came from the fact that rivers can be dangerous and changeable things and crossings were not always in the state you'd hope for when travellers reached them.
The stepping stones at Bolton Abbey are probably the most famous, but you'll find many others through out the Dales, some half-hidden by the flow of the river.
They would have been a hazardous and unreliable way to cross, often only passable with a wooden staff to keep one's balance.
You'll notice some over streams which were paved for more frequent use, often leading to a house or settlement.
After the Romans, one of the most common reasons for travelling around the Yorkshire Dales was to trade wool or sheep, something at which the landowning monks were adept. They're likely to have built some of the earliest bridges.
You can see clapper bridges in Austwick, Malham and Linton. They were mostly built using slate for the convenience of locals across narrow and shallow rivers or streams.
Some bridges were initially built using timber but were replaced with stone when the wood rotted,
In the 18th century the Turnpike Trusts were given the power to collect tolls making it worthwhile to improve roads and bridges, making them better and broader.
You might associate suspension bridges with Hull or other bigger cities but we have at least two in the Dales, one in Reeth, known as the Swing Bridge and the other across the river Wharfe near Linton.
The suspension bridge across the river Wharfe was created after a local man drowned trying to cross the stepping stones. It was designed and built by the village blacksmith using over 250 metres of old steel rope, bought from a mining company.