Water surged down Broad Street during the 1960 flood
This summer's special exhibition at Newtown Textile Museum focuses on its collection of postcards and photos of floods and flood defences in Newtown.
There are pictures of the early flooding in 1908 and the two serious floods in 1960 and 1964.
It was the latter two disasters which prompted the building of flood defences starting in 1966 and continuing through the early 1970s.
Photographs from the work on those defences are also on display.
The exhibition has been arranged by local historian David Pugh, who has researched the topic and put together text and labels for all the photographs.
Mr Pugh said the exhibition was timely because this year marks the 50th anniversary of the 1960 flood , which took place on Saturday 3 December and the following day.
The river Severn cut across its loop round the town and rushed through the town centre destroying many of the town's shops and carrying away stock in its wake.
Mr Pugh added: "Telegraph poles were stored in a building where the bus station now stands and these were taken away by the flood water.
"The telegraph poles acted like torpedoes and smashed into many buildings causing untold damage.
"At the time the people of Newtown were told that the flood was a freak occurrence and wouldn't happen again for another 150 years but they were wrong because it happened again four years later," said Mr Pugh.
"The problem was that Newtown was a medieval town built by the Marcher lord, Roger Mortimer, which had an excellent defensive feature because of its proximity to the river Severn.
"Unfortunately this also meant that the town was always susceptible to flooding."
The second torrent took place on Saturday, 12 and Sunday, 13 December 1964.
According to Mr Pugh the second flood meant that shopkeepers could no longer get insurance for their businesses and the town council could not afford to pay for flood defences.
"Many people felt that the town was doomed and the town would have to be abandoned," he added.
But the 1965 New Towns Act designated that Newtown should be made a new town and, as a result of this, the government decided to protect the town with a major flood prevention scheme.
The exhibition runs until September 2010. The museum's opening hours are from 2 to 5pm on Monday,Tuesday Thursday, Friday and Saturday each week.