Did you know that Windows 10 allows you to display the time from various cities and countries as a tile in the Start menu? There are no third party tools required. Everything can be done with apps you already have.
You need to start the Alarms & Clock app. It is a preinstalled Universal Windows Platform app. One of its features is a useful World Clock.
Open the Start menu and launch the application from there:
Once this is done, you can pin the added locations to the Start menu in Windows 10. They become Live Tiles which show the actual time in the selected cities!
Pin a World Clock Tile to Start Menu in Windows 10
Right click the desired city on the World Clock page of the Alarms & Clock app.
From the context menu, select "Pin to Start". You'll need to confirm the operation:
Enjoy your Live Tiles with the World Clock:
This is very useful for people who work with other people in different parts of the world or have friends there. Now the world time is just one click away from you. Credits for this tip go to Digital Citizen.
Tip: Windows 7 and Windows 8.1 users can have this feature too in the Date and Calendar popup on the taskbar. From Date and Time Control Panel, you can add additional clocks for two time zones.