Calendar List is Missing in SharePoint 2010

How to fix this issue?

Issue

Calendar list is Missing in SharePoint 2010.

Reason

The required "site feature" may not be activated in the SharePoint portal.

Solution

1. Go to the "Site Settings"
2. Go to "Manage Site Features"
3. Check "Group Work Lists" feature is activated or not. If not, Activate
   the feature.

Update

If you are not able to view / create lists or document library or task library, you need to activate the "Team Collaboration Lists" site feature.