21st century travel is as much about what you download as what you pack. These apps are free and come recommended.
PLANNING TRAVEL
Flights– SkyScanner
Hostels–HostelWorld
Organizing your travels/maps/itinerary–Google Trips
Tips from travellers–FourSquare
THINGS TO DO
Theatre tickets–TodayTix
Gigs (concerts)–YPlan
TRANSPORT
Transport in London/other cities–CityMapper
Cheap taxis–Uber
LANGUAGE
Translation (including translations using camera)–Google Translate
Help pronouncing something–HowJSay
COMMUNICATIONS
Seeking Wifi– Wi-Fi Finder
Free/ cheap calls with internet connection–Viber
Cheap calls without internet connection–Rebtel
MONEY
Currency Conversion–XE Currency
Help calculating what to tip–Tipulator
SAFETY
Major/ medical emergencies–CitizenAid
To help contact police or embassies–TravelSafe