I found this a really useful guide and would look out for Marco Polo again when going somewhere new. Without this guide I wouldn't have known about the Hypogeum and the need to pre-book it as they can only allow 80 people in per day. It was well worth seeing and just this made it worth having the guide. I drove to Gozo and the guide took me to some fascinating places. I would totally recommend it. I also bout the Insight flexi map which I would recommend too as it also got a lot of use.