iOS: Modern Atlas is one of many trip-planning apps that can organise what you want to see, do and eat during your next holiday. Its focus is on the research portion, and gives you a ton of information about your destination that you can use to plan the perfect trip. You can use Modern Atlas in two main ways: To find out about your destination before you leave and plan things like where you'll stay, eat and sightsee, or to find out what interesting stuff is around you in the moment. Either way, you'll get a lot of information, including from how to get to a point of interest to the history of that spot to how to stay safe once you get there. There's even a section called "Go Next" which suggests nearby cities or sites you may want to visit and tells you how to get there.
Modern Atlas draws its information from sites like Wikipedia, Foursquare and Wikivoyage, so some sections may be incomplete or not 100 per cent accurate. For example, I tried out the app by checking out Capri, somewhere I've been before, and found the section on art and culture empty. Each destination has photos (pulled from 500px) you can check out, but I found many of them to be overly edited and not representative of what you'd actually see in person.
You can save your bookmarked places in a map for each trip you plan, making it simple to reference later. There's also a 3D mode if you want to see the map with a Google Satellite-esque view. Overall, Modern Atlas combines a huge amount of useful information into one place for easy trip research and planning.