Even if your guidebook covers the city you're exploring, there's a lot more to the place than the editors actually put in the book. Take the time to explore local neighborhoods and try to experience the daily life of people who live there. There are no foreign lands. It is the traveler only who is foreign . We all know this, but sometimes we all need to be reminded.
Different countries have different sets of rules - sometimes shorter sets of rules.
In the interest of being both culturally sensitive and safe, immediately familiarize yourself with the laws and customs of the places you travel and adhere to them the best you can. As a professional photographer who likes to travel light as well as take quality photographs for my portfolio, I have found out the hard way which equipment I really need, and which equipment is best left at home. If 2 lenses can fit the pack, then I would add an 80mm to 200mm zoom for portraits and close-up work.