A museum (plural museums or, rarely, musea) is an institution that cares for (conserves) a collection of artifacts and other objects of artistic, cultural, historical, or scientific importance. Many public museums make these items available for public viewing through exhibits that may be permanent or temporary. The largest museums are located in major cities throughout the world, while thousands of local museums exist in smaller cities, towns, and rural areas. Museums have varying aims, ranging from serving researchers and specialists to serving the general public. The goal of serving researchers is increasingly shifting to serving the general public.