1. something erected in memory of a person, event, etc., as a building, pillar, or statue

2. any building, megalith, etc., surviving from a past age, and regarded as of historical or archaeological importance.

3. any enduring evidence or notable example of something.

4. an exemplar, model, or personification of some abstract quality, especially when considered to be beyond question.

5. an area or a site of interest to the public for its historical significance, great natural beauty, etc., preserved and maintained by a government.