1. The White Spaces the Boy Pointed To
In the novel *Heart of Darkness*, there is a memory of a boy who loved maps. He would stare at maps of South America and Africa for hours, placing his finger on the white spaces that attracted him most, and saying he would go there when he grew up. [1] This novel was serialized in a magazine in 1899. [2]
White spaces are places where nothing is drawn on the map. Are there no people there? Has no one gone there? Or has it simply not been measured? To understand this, let us look at the stories of people who actually entered these white spaces.
2. Many People Lived in the Valley That Was Supposed to Be Empty
Until about 90 years ago, the interior of New Guinea Island was thought to be nothing but “steep mountains and damp jungle.” [3] Mick Leahy and other Australians, who came looking for gold, entered the mountains believing it was land where no one lived. [4] In February 1933, Leahy’s group looked down from a mountain and found a wide valley full of people. [3]
This highland area is introduced as having about 1 million people living there. [4] According to the commentary, the people in the highlands did not know about the outside world and were seeing outsiders for the first time. [4] White spaces on maps were not necessarily places with no one. From the perspective of the people in the valley, the outside world was the place they did not yet know.
The Son Doong Cave in Vietnam is another example. A local man found the entrance in 1990, and an international survey team entered in 2009 with his guidance. [5] However, we cannot say that all white spaces were like this. So, do any white spaces remain on today’s maps?
3. Land Maps Were Filled In from Space
Walking people were not the only ones to fill in the white on maps. In 1972, the United States launched the Earth observation satellite ERTS-1 (later Landsat 1). [6] The observation was planned for 1 year but continued for about 6 years, and the images taken covered about 75% of the Earth’s surface. [6]
In February 2000, the Space Shuttle Endeavour used radar during an 11-day flight to measure the height of the land. It measured about 80% of the land between 60° North latitude and 56° South latitude. [7] The data was collected at a fine resolution of about 30 meters per point. [7] [8]
This happened about 100 years after the 1899 novel. However, this observation only reached between 60° North and 56° South latitude. Also, having a height map is different from people actually going there.
4. Why Do Unclimbed Mountains Remain?
Gangkhar Puensum in Bhutan is 7,570 meters high. It is said to be the highest mountain in the world with no record of a summit. [9] [10] Bhutan began accepting mountaineering in 1983, and four expeditions tried to climb it between 1985 and 1986, but none reached the top. [9] [10]
After that, Bhutan banned climbing mountains higher than 6,000 meters in the mid-1990s. Since 2003, mountaineering itself has been banned. [9] [10] This is explained as being due to a belief that mountains are the dwelling places of gods or spirits. [9] [10]
This mountain remains white not only because people could not go there, but also because the country bans climbing. We could not find a number that counts the total percentage of places humans have not yet set foot in. There are also places in caves that are still being explored.
5. The Biggest White Space Is the Ocean Floor
The largest white space today is the bottom of the sea. The Nippon Foundation and the international initiative GEBCO started the Seabed 2030 project in 2017 to complete a map of the ocean floor by 2030. [11] When it started, only about 6% of the ocean floor had been measured at the required resolution. [11] In April 2026, the figure was reported as 28.7%. [13] It increased by nearly 5 million square kilometers in one year, but about 70% remains unmapped. [13]
Measuring is difficult because light only penetrates a few hundred feet into the sea. [14] The method of taking photos from the sky cannot be used. Instead, ships send out sound and measure the depth by the time it takes for the echo to return. [15]
Satellites can estimate rough terrain from gravity differences caused by large underwater mountains, but details are blurry. [15] GEBCO writes that it is often said that the surface of Mars is better known than the shape of Earth’s ocean floor. [16]
On January 23, 1960, a submersible carrying Jacques Piccard and Don Walsh reached the bottom of the Challenger Deep, the deepest point. They reportedly stayed at the bottom for about 20 minutes. [17] Going there and measuring it in detail are different things.
6. Settlements Were Hidden Under the Forest
Even if you fly over a forest, photos only show leaves. That is why LiDAR is used. It measures distance by the time it takes for a laser from an airplane to bounce back to the ground. [18] Some lasers pass through gaps in the leaves and reach the ground, so computers can remove the trees to reveal the shape of the land. [18] [20]
In the forests of northern Guatemala, an area about the size of Tokyo was measured by laser in 2016, and traces of more than 60,000 buildings and roads were found. [20] [21] Some researchers now estimate the Maya population to be higher than previous estimates. [20]
In the Upano Valley in Ecuador, about 6,000 earth platforms, 15 settlements, and roads connecting them were found under the forest. People seem to have lived there for about 2,000 years, starting around 500 BC. [22] [23] Researchers like Rostain had been digging up mounds in this valley for decades. Measuring from above revealed the full extent. [23] [24]
So, how far have humans walked the Earth? The meaning of white spaces has changed over time. In the past, it meant “not drawn on the map.” Today, it means the ocean floor “not measured in detail,” mountains with “no summit record,” and forests where “we do not know what is under the leaves.” In the highland and forest examples, people lived under the white spaces. It seems we cannot yet say we have walked every inch.
7. Checking White Spaces on Screens and With Your Feet
You can check the white spaces on the ocean floor on a computer with an adult. The University of New Hampshire’s “BathyGlobe” shows oceans that have been measured with multibeam sonar and have open data on a globe. [25] Compare areas near Japan and the middle of the Pacific. Do the marked and unmarked areas match your expectations?
You can see your own town on the Geospatial Information Authority of Japan’s “GSI Maps” by selecting “Shaded Relief Map” under “Elevation and Terrain Relief.” [26] This is a black-and-white map with shadows that makes bumps and dips in the ground easy to see. [26]
It may be good to walk the slopes and hills you see on the map during daylight hours with an adult. For safety, when going to places seen on a map, choose roads you have walked before, go during daylight, and stay with an adult. Do not go near rivers or the edges of cliffs.