Six buildings and landscapes have been added to the English Heritage "at risk" register to save them for future generations.
Uxbridge Lido in west London, Lowther Castle and Birkrigg Stone Circle, both in Cumbria, and Newbury Battlefield in Berkshire, are new additions.
Part of Pindale lead mine in Derbyshire and Salcombe Cannon site, off the coast of Devon, are also included.
The full list of sites will be announced in July.
Previously only Grade I and Grade II* listed buildings were included.
But for the first time the new Heritage at Risk Register will cover Grade II listed buildings, monuments, archaeology, landscapes, places of worship and maritime wrecks.
It follows a major study of thousands of historic sites across England.
An English Heritage spokeswoman said the six case studies revealed on Monday, had been highlighted because of their special interest.
Uxbridge Lido is England's only remaining example of a 12-sided 'star' swimming pool.
At 220ft (67m), it is the second longest open-air swimming pool remaining in London.
Despite being covered in graffiti, there are plans to refurbish the lido as part of a £22m sports development.
Lowther castle was built in the early 1800s but now lies derelict
Newbury Battlefield was the site of the 1643 First Battle of Newbury during the English Civil War.
The site, which is thought to contain the mass graves - yet to be located - of the soldiers who fell, is at risk from new residential development, English Heritage said.
Lowther Castle ruin, near Penrith, was built for the fifth Earl of Lonsdale, Hugh Lowther, between 1806 and 1814, but has been unoccupied since 1942.
Emergency repairs have been completed to prevent a collapse of the derelict building.
Birkrigg Stone Circle, overlooking Morecambe Bay, dates from between 1700 and 1400 BC and is one of about 50 stone circles in Cumbria.
The site's 31 stones are at risk due to spray-painting vandalism.
Gold treasure, including a large haul of Islamic coins, was found in 1995 at Salcombe Cannon site, a shipwreck which lies on the seabed off the Devon coast.
It is thought the ship sank in the mid 17th Century. In 2007 the site was severely damaged by an unauthorised fishing vessel operating within the site's restricted area.
Pindale side veins, the remains of a 17th Century lead mine near Castleton, is at risk of damage from trail bikers and vehicle dumping.
Dr Simon Thurley, Chief Executive of English Heritage, said: "Heritage at Risk is not a name and shame exercise.
"The new register will focus everyone's attention on the neediest cases, bringing the owners, councils and others together and harnessing the nation's huge enthusiasm for its rich, varied but sometimes fragile past."
Buildings and sites added to the register do not necessarily get new funding but English Heritage hopes it will highlight their cases and encourage groups to provide financial support.