 The CAMRA Pub Heritage Group identifies, records and helps to protect pub interiors of historic and/or architectural importance, and seeks to get them listed.The group maintains two inventories of Heritage pubs, the National Inventory (NI), which contains only those pubs that have been maintained in their original condition (or have been modified very little) for at least thirty years, but usually since at least World War II.The second, larger, inventory is the Regional Inventory (RI), which is broken down by county and contains both those pubs listed in the NI and other pubs that are not eligible for the NI, for reasons such as having been overly modified, but are still considered historically important, or have particular architectural value.