Geograph - photograph every grid square

Listed buildings and structures are officially designated as being of special architectural, historical or cultural significance. There are over half a million listed structures in the United Kingdom, covered by around 375,000 listings.
Listed status is more commonly associated with buildings or groups of buildings, however it can cover many other structures, including bridges, headstones, steps, ponds, monuments, walls, phone boxes, wrecks, parks, and heritage sites, and in more recent times a road crossing (Abbey Road) and graffiti art (Banksy 'Spy-booth') have been included.

In England and Wales there are three main listing designations;
Grade I (2.5%) - exceptional interest, sometimes considered to be internationally important.
Grade II* (5.5%) - particularly important buildings of more than special interest.
Grade II (92%) - nationally important and of special interest.

There are also locally listed structures (at the discretion of local authorities) using A, B and C designations.

In Scotland three classifications are also used but the criteria are different. There are around 47,500 Listed buildings.
Category A (8%)- generally equivalent to Grade I and II* in England and Wales
Category B (51%)- this appears generally to cover the ground of Grade II, recognising national importance.
Category C (41%)- buildings of local importance, probably with some overlap with English Grade II.

In Northern Ireland the criteria are similar to Scotland, but the classifications are:
Grade A (2.3%)
Grade B+ (4.7%)
Grade B (93%)

Read more at Wikipedia Link

The River Severn is the longest river in the United Kingdom, at about 220 miles. It rises at an altitude of 610 metres on Plynlimon, in the Cambrian Mountains of mid Wales. It then flows through Shropshire, Worcestershire and Gloucestershire, with the county towns of Shrewsbury, Worcester, and Gloucester on its banks.
The river is usually considered to become the Severn Estuary after the Second Severn Crossing between Severn Beach, South Gloucestershire and Sudbrook, Monmouthshire. The river then discharges into the Bristol Channel.

The National Cycle Network is a network of cycle routes. It was created by the charity Sustrans Link (Sustainable Transport), aided by a National Lottery grant.

Many routes aim to minimise contact with motor traffic, though 70% of them are on roads. In some cases the NCN uses pedestrian routes, disused railways, minor roads, canal towpaths, or traffic-calmed routes in towns and cities.

The River Severn is the longest river in Britain, at about 354 kilometres (220 miles). Its source is on Plynlimon near Llanidloes, Powys, in the Cambrian Mountains. It then flows through Shropshire, Worcestershire and Gloucestershire. The Severn is the greatest river in terms of water flow in England and Wales.

National Cycle Network route 45 stretches for 276 miles from Chester to Salisbury, passing through Worcester and Swindon.

More information is available on Sustrans' website: Link

The village of Ironbridge, in the Severn Gorge, is key to the Industrial Revolution which took place during the 18th Century. In the early part of the century, an ironmaster called Abraham Darby discovered that iron could be smelted using coke from Coalbrookdale, instead of charcoal. Then, in 1779, the world's first iron bridge was built spanning the Severn Gorge. The village takes its name from the bridge. In recogntion of its contribution to the Industrial Revolution, Ironbridge has been granted UNESCO World Heritage Site status.

More information about Ironbridge and its history can be found on the website of English Heritage: Link The Ironbridge Gorge Museum Trust's website Link also has some information, as does the UNESCO website: Link

In the United Kingdom, a scheduled monument is a 'nationally important' archaeological site or historic building, given protection against unauthorised change.
There are about 20,000 scheduled monuments in England representing about 37,000 heritage assets. Of the tens of thousands of scheduled monuments in the UK, most are inconspicuous archaeological sites, but some are large ruins.
Wikipedia: Link