You Do Need power plug adapter while traveling from Guyana to Vatican City.

Here is Why You Need An Adapter

The outlet and plug type used in Vatican City are C, F and L and in Guyana are A, B, D and G. This is how they look like.

Guyana

In Guyana, outlets of type A, B, D and G are in use.

Type A

Type B

Type D

Type G

Vatican City

In Vatican City, outlets of type C, F and L are in use.

Type C

Type F

Type L