Set opposite Diglis Island, in Worcester, Diglis Fish Pass is the only underwater viewing gallery of its kind in the UK.
This feat of modern engineering first opened in 2021 and offers visitors the chance to spot a variety of fish as they pass by its viewing window.
Fish use this to bypass Diglis Weir as they head upstream - saving vital energy on their journey.
From large salmon, perch and bream to the unique-looking sea lamprey, an eclectic range of fish have been spotted at Diglis Fish Pass since it opened.
I was keen to try the free drop-in sessions held by Unlocking The Severn, a conservation project that also operates 90-minute Diglis Island and Fish Pass tours across the year.
The free drop-in sessions take place every two weeks and there are two more scheduled for the second half of October.
The entrance to Diglis Fish Pass is located alongside the river toward the end of Bromwich Parade, and the entrance takes you 'below deck' where a four-inch-thick viewing window awaits.
Sadly, days of wet weather impacted my visit to Diglis Fish Pass, as the well-informed volunteer on-site told me that water levels in the river Severn had risen by a foot in recent days and were moving quickly making visibility difficult.
Visibility was made more challenging with a deep orange colour filling the window due to algae and debris.
After a few minutes of waiting alongside another family who had dropped in, a perch flew past to make the visit all the more worthwhile.
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Alongside viewing seats, Unlocking The Severn and its volunteers offer plenty of information about the project and the variety of fish that, with some luck, can be seen on any given day.
The spring and summer months were highlighted as the best times to enjoy Diglis Fish Pass during my visit and the volunteer told me that May, June and July was the main migrating period for fish.
Two more drop-in sessions are scheduled for this month including Wednesday, October 16 and Wednesday, October 30 from 2pm until 4pm.
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