Leaflet
Leaflet is an easy to use mapping library written in JavaScript. It allows you to render map data to an HTML element and works well on mobile devices. Developed in 2011 by Vladimir Agafonkin, it allows you to overlay your data onto static map tiles.
Leaflet uses a concept known as Tiled Web Map, or Slippy Map. The basic idea was developed by Google for their maps project back in 2005. Mapbox has a great resource on how map tiles work at https://www.mapbox.com/help/how-web-maps-work/. These map tiles provide the background map that we'll plot our data on.