Street photography of general scenes, markets and monuments is legal in most countries, but the details differ enough that a quick check of your destination is worth it. A few countries restrict photographing infrastructure like bridges, stations or ports; others have privacy laws that technically require consent before publishing recognizable photos of people, even taken in public.
Etiquette matters as much as law. Vendors in markets generally tolerate wide shots but appreciate being asked before close-ups of them or their goods, and buying something small first goes a long way. Photographing children is sensitive almost everywhere; always ask a parent. Some communities and religious groups object to photography on cultural grounds, so a raised hand or a head shake means put the camera away, no debate.
Tripods and drones are separate issues: many attractions ban tripods without a permit, and drones are heavily regulated or banned outright in numerous countries. If your trip depends on either, look up the official rules before you pack them.