Today, bridges are a vital part of the road network linking the Perthshire and Angus glens to the southern side of Strathmore and Dundee.
Before they were built, travellers had to rely on fords and ferries which were both unreliable and dangerous in bad weather.
One account from 1791 describes a ferry over the River Isla on the road from Alyth to Dundee which passes through Meigle. This was eventually replaced by Crathie Bridge at the beginning of the 19th century.
In the mid-1800s, a new bridge was built across the Dean Water at Cardean but when people continued to use the medieval, so-called ' Roman Bridge' in order to avoid paying the toll, the owner of Cardean, Admiral Popham, destroyed the bridge using explosives. James Cox had the bridge rebuilt when he later bought Cardean.
Even today roads across the Isla can be blocked by flooding caused by heavy rain and melting snow.
Crathie Bridge
Old Balmacron Bridge