Mapillary - Street-level imagery, powered by collaboration and computer vision.
Street View - 360 degree views of various places.
The True Size Of - Compare the relative size of countries.
OpenTopoMap - Free topographic maps.
OpenCycleMap - Global cycling map for overview and planning.
OpenSeaMap - Free nautical chart.
OpenRailwayMap - Free map of the world's railway infrastructure.
Zugverfolgung.com - Live train tracking for Germany, Austria, Switzerland Netherlands, and Belgium.
Rail Radar - Real time movements of trains in the UK.
Track Your Train Map - Live train tracking in the US.
Flightradar24 - Real time flight tracker map.
ISSTracker - Real-time location tracking of the international space station.
Satellite Map - Current position and trajectory of 16,000 manmade objects orbiting the earth.
OpenTripMap - Map service for sightseeing and travel planning.
Wikimapia - Editable map of marked places.
Open Camping Map - World map of camping sites.
mundraub - Edible plants and fruits worldwide.
Windfinder - Wind forecasts, wind radar, wind force and weather.
Windy - Wind map, weather forecast and more than 40 other layers.
Real Time Lightning Map - Lightning strikes in real time across the planet.
OpenWeatherMap - Interactive weather maps.
Zoom Earth - Weather and historical maps.
Planet Explorer - Daily map, paid.
Earth Nullschool - Wind and weather map.
Earthquake Track - Map of earthquakes.
Forest Watch - Monitoring of forest and land fires.
Live Cyber Threat Map - Live map of cyberattacks.
NUKEMAP - Simulate explosions of nuclear weapons.
Missilemap - Simulate of missile reaches
Million Neighborhoods - Map of slums or informal settlements.
Sprawl Map - Mapping the effect of urbanization.
Stellarium Web - Virtual online planetarium.
Moon Trek - NASA exploration portal for the moon.
Mars Trek - NASA exploration portal for the Mars.
3D Solar System Simulator - Orbits of planets and more than 150 comets and asteroids.
Solar System Scope - Solar system, night sky and outer space in real time.
100,000 Stars - Interactive visualization of the stellar neighborhood.
The Universe in 3D - Interactive 3D map of the universe.
Open Layers - App to put a dynamic map in any web page. It can display map tiles, vector data and markers loaded from any source
Switch2OSM - Campaign and help docs for using OSM