Replaced the underlined word with a suitable word.
The tranquillity and sanctity of the place soothed us.

The word 'sanctity' means the state or quality of being holy, sacred, or saintly. Therefore, 'Holiness' is the most suitable replacement.
* 'Security' means safety from danger or threat.
* 'Equanimity' means mental calmness and composure.
* 'Placidity' means a calm and peaceful quality (similar to tranquillity).