Look closely at the porthole door on the right to see the holes that were used to lash a screen or covering over the doorway. To the left is an odd opening that combines both a trilithon (3-stone) door and a porthole door, which lead to a tiny niche. This trilithon / porthole door can be seen on the Maltese 5-, 2-, and 1-Euro coins. The metal apparatus on the right tracks changes in temperature, humidity, etc. Back in 1994, heavy rainfall led to the collapse of a wall in this chamber, so Malta’s Heritage Parks monitor the temples’ environments to better protect them.