It all started with an idea by German geographer Albrecht Penck who proposed a worldwide system of maps at the Fifth International Geographical Conference in 1891. His solution, called the International Map of the World, would consist of 2,500 individual maps, each covering four degrees of latitude and six degrees of longitude at a scale of 1:1 million (1 cm = 10 km). But it wasn’t until 1913 that Penck's idea came to fruition when an international conference in Paris established standards for the maps, which became also known as the Millionth Map of the World due to the map series' scale.
Australian version of Topo 1M map by Geoscience Australia
The standards required that maps would use the local form of place name in the Roman alphabet (thus, mandating translation of local names from languages that use other alphabets). Map colours were also standardized so towns, railroads, and political boundaries would be represented in black, roads would be red, and topographic features would be brown. Individual maps were to be indexed according to a common system (used to this day).
It was agreed that each country would be responsible for create their own maps but not many countries had the capacity to undertake this task so, a lot of early maps were created by a handful of Anglo-Saxon countries. By the 1930s, 405 maps had been produced although only half adhered to the standards of the project. The newly-created United Nations took control of the Millionth Map project in 1953 but the international interest creating the maps kept waning over the following decades. By the 1980s, only about 800 to 1000 total maps had been created (and less than half were accurate or based on the standards), and the U.N. stopped issuing their regular reports about the status of the project.
The data captured over the past 10 decades and used in the production of the Millionth Map of the World filtered through to many projects and formed the basis of VMap0 GIS dataset and other derived products. It is hard to get excited about 1:1M scale maps any more when you have Google Maps but let’s not forget that just 8 years ago, before Google created the world map at street level accuracy and before OpenStreetMap started its crowdsourcing initiative, this was the highest resolution available which was of consistent quality for almost the entire world. Although 1:1 million scale is not suitable for navigation purposes, maps at this and smaller scales remain popular choice as general reference maps, or as a backdrop for thematic mapping, or for various infographics.
Index to International Maps of the World
Information sourced from About Geography