What does "worth doing" mean?

Hello !! Tell me please, the expression’ it is worth seeing’
‘it is worth reading’, etc
always are followed by ing-form of verb ?(seeing, reading,etc)

Thank you for you help.


Hi Pupil,

‘Worth doing’ means literally there is value/benefit in doing something. When you travel to Egypt, it’s worth seeing the pyramids - in other words it’s a good idea.