Click History.

Select the History button to view the history for the page you are currently viewing.
View page history.
Page history displays the following information:
- Gives a list of all previous versions of that page, with the name of the user who altered it and the date.
- Allows you to view any previous version.
- Compare the contents of any version with the current version.
- Compare the contents of any version with the version immediately previous, to see what changes were made by each user.
- Allows you to revert to any previous version.
Tip: If you have accidentally deleted content from your page, you can use the "Revert to this version" option to revert to an earlier, correct version, for example.