Point to the people you love
Which way, and how far below the horizon, loved ones abroad really are
On a map, the way to someone far away looks like a line across the paper. The truly straight line runs through the Earth: from Bucharest to London it dips 9.4° below the horizon and reaches 86 km down, near where Czechia, Austria and Germany meet. Pick where you are pointing from, and at whom.
Turn to the west-northwest, 301° from north,
and lower your arm 9.4° below the horizon.
The straight line to London is 2,087 km long and reaches 86 km down, near where Czechia, Austria and Germany meet. Along the surface it is 2,096 km.
On a flat map you would have pointed west-northwest (292°), 9° off.
The phone guides you by compass and buzzes (on Android) when you point straight at London.
Scan the code with your phone: the page opens with the same places and guides you by compass until you point straight at London.
What lies between you: underneath and on top
The straight line runs beneath everything on the map. The deepest hole ever drilled straight down, the Kola borehole in Russia, reaches 12.3 km. The line from Bucharest to Chișinău dips about 2.5 km; the line to London, 86 km.
Under Romania the crust is 25 to 50 km thick: thinnest in the western plain and towards the Danube, thickest under the Carpathians and the Focșani Depression. Below it lies the mantle, hot rock that flows slowly over millions of years. Romania’s big Vrancea earthquakes start down there, roughly 60 to 180 km deep; Straight down (in Romanian) maps each one.
Underneath
On top
Why the direction is not the one on the map
Many wall and web maps use the Mercator projection, which keeps angles but enlarges areas more and more towards the poles. A line ruled across it cuts every meridian at the same angle; the shortest way on the globe (a great-circle arc on a sphere, a geodesic on the ellipsoid) leaves Bucharest further north and bends back.
The further away the place, the bigger the gap. For Toronto the map says almost due west (269°), while the straight line leaves to the north-west (312°): 43° apart. For Melbourne the map says south-east (127°); the line says east-south-east (103°).
How far down: the rule you can check
On a sphere, the straight line dips below the horizon by exactly half the angle at the Earth’s centre between the two places. That angle is the surface distance divided by the Earth’s radius: for London, 2,096 km ÷ 6,371 km = 0.329 radians, or 18.9°; half of it is 9.4°. The page works on the ellipsoid GPS uses; for the cities on this page it differs from the sphere by at most 0.3°.
How far away someone must be for the line to cross the mantle or the core
While places are close, the depth grows roughly with the square of the distance; further out it grows less than that rule would say. At the antipode the line is as long as the diameter, 12,742 km, and passes through the Earth’s centre, 6,371 km down. The thresholds below are on a 6,371 km sphere; “crust” means the crust under Romania.
| Distance along the surface | The straight line reaches |
|---|---|
| 791 km | the depth of the Kola borehole (12.3 km) |
| 1,597 km | below the crust anywhere in Romania (at most 50 km) |
| 3,070 km | below the deepest Vrancea earthquake in the catalogue (184 km) |
| 5,896 km | into the lower mantle (670 km) |
| 12,652 km | into the outer core, molten iron (2,891 km) |
| 17,557 km | into the inner core, solid iron (5,150 km) |
For people in Toronto or New York, the line from Bucharest goes more than 1,100 km down, into the lower mantle. For Melbourne it crosses the outer core, the molten iron whose motion makes most of the Earth’s magnetic field: the same field the phone’s compass reads to show you the way. Experiments on melting mantle rock put the temperature at the boundary between mantle and core at about 3,500–4,200 kelvin. To find out what falling through such a tunnel would be like, see Jump into a hole through the Earth.
Which way Romania points: by the UN’s count, 4,583,819 people born there live in another country
This is what the people the UN counts as having left look like from under your feet. The centre of the circle is straight down, the edge is the horizon; each patch is a country, its area proportional to the number of people born in Romania who live there, by the UN’s 2024 estimate. The white target is the place chosen above.
From Bucharest (each country counted at its largest city), 81% of them are less than 10° below the horizon, and 97% are somewhere to the west (72% between south-west and north-west). If they all pointed at once, the average arrow would aim west-northwest (292°), 10.3° below the horizon.
Each country is represented by its largest city (Berlin for Germany, though many who left Romania live in the south). The count is of people born in Romania, whatever their ethnicity or present citizenship; for a few countries with small counts (Japan, Libya, San Marino) the UN counts citizenship instead. The UN lists “Romania” as a separate origin in only 69 countries, so people in Ukraine, for example, are missing; and Hungary’s figure is an extrapolation, above the nearly 208,000 counted by Eurostat.
| Country | Born in Romania | City | Direction | Below horizon |
|---|---|---|---|---|
| Germany | 968,697 | Berlin | 318° northwest | 5.8° |
| Italy | 880,402 | Rome | 260° west | 5.1° |
| United Kingdom | 713,578 | London | 301° west-northwest | 9.4° |
| Spain | 522,578 | Madrid | 270° west | 11.1° |
| Hungary | 253,045 | Budapest | 304° northwest | 2.9° |
| United States | 178,498 | New York City | 307° northwest | 34.4° |
| Austria | 160,281 | Vienna | 303° west-northwest | 3.8° |
| France | 156,668 | Paris | 294° west-northwest | 8.4° |
| Belgium | 131,417 | Brussels | 301° west-northwest | 8.0° |
| Israel | 116,289 | Jerusalem | 147° south-southeast | 7.3° |
| Canada | 88,282 | Toronto | 312° northwest | 34.9° |
| Netherlands | 55,421 | Amsterdam | 307° northwest | 8.0° |
| Greece | 50,056 | Athens | 196° south-southwest | 3.3° |
| Ireland | 47,700 | Dublin | 304° northwest | 11.4° |
| Denmark | 40,659 | Copenhagen | 327° north-northwest | 7.1° |
| Switzerland | 40,167 | Zürich | 290° west-northwest | 6.3° |
| Sweden | 38,394 | Stockholm | 345° north-northwest | 7.8° |
| Portugal | 29,376 | Lisbon | 270° west | 13.4° |
| Norway | 16,537 | Oslo | 335° north-northwest | 9.0° |
| Australia | 15,735 | Sydney | 95° east | 68.4° |
How it is calculated, and how far to trust the phone’s compass
Geometry. Positions are on the WGS84 ellipsoid used by GPS. Surface distance and the shortest path come from Charles Karney’s algorithm (GeographicLib). The straight line is the segment between the two points in Cartesian coordinates; its angle below the horizon is measured from the local vertical, and its direction is the one in which the segment leaves. Heights are ignored: standing on a 500 m hill changes the angle to London by about a hundredth of a degree.
Compass. Phones point to magnetic north, not true north. The page adds your local magnetic declination from the World Magnetic Model 2025 (NOAA and the British Geological Survey); in Bucharest it is 6.4° east. Published measurements give a phone compass errors of a few degrees outdoors after calibration, 10–30° on average in everyday use, and more near metal; tilt is far more accurate, about 2°. So the target accepts 10° of direction and 4° of tilt. It works best outdoors or at a window, away from cars and radiators; if the phone asks, move it in a figure of eight.
Places. Romanian places are the seats of its 3,181 communes and towns, positioned from OpenStreetMap; world cities have over 15,000 people (GeoNames), with names from Wikidata. Borders are from Natural Earth. Everything is calculated on your phone or computer. The page does not send the places you pick to any server: they are kept in the page address after the # sign, and leave your device only if you share the link.
Inside the Earth. Layer radii come from the PREM reference model (Dziewonski and Anderson, 1981): inner core to 1,221.5 km from the centre, outer core to 3,480 km, the 670 km boundary between upper and lower mantle. Crustal thickness under Romania comes from the compilation by Răileanu, Ionescu and Tătaru (2008) and the VRANCEA99 and VRANCEA2001 seismic profiles.
The diaspora. Counts are the UN estimate (International Migrant Stock 2024) of people born in Romania usually resident in another country (typically for at least a year); where a host country has no data by place of birth, the UN uses citizenship. Hungary, Greece, Portugal and Norway are extrapolated from the 2020 edition.
The straight tunnel through the Earth is an old calculation found in many online calculators (PlanetCalc, Antipodes Map, The Math Doctors); here it is turned towards one particular person and put in your hand.
Sources
- UN DESA, International Migrant Stock 2024 (destination and origin)
- NOAA NCEI / BGS, World Magnetic Model 2025
- C. F. F. Karney, GeographicLib (geodesics on the ellipsoid)
- A. M. Dziewonski, D. L. Anderson, Preliminary Reference Earth Model, PEPI 25 (1981)
- V. Răileanu et al., crustal structure along VRANCEA99/VRANCEA2001 (EGU 2006)
- V. Răileanu, C. Ionescu, D. Tătaru, Moho depth in Romania (EGU 2008)
- W. D. Mooney, Crust and lithospheric structure, Treatise on Geophysics (2007)
- Smithsonian Magazine, What’s the deepest hole ever dug? (Kola, 12,262 m)
- B. Ferrand, M. Manea, Vrancea intermediate-depth seismicity, Scientific Reports (2021)
- R. Nomura et al., Low core–mantle boundary temperature, Science (2014)
- G. Fiquet et al., Melting of peridotite to 140 GPa, Science (2010)
- British Geological Survey, The Earth’s magnetic field: an overview
- W3C, DeviceOrientation Event Specification
- J. R. Blum, D. G. Greencorn, J. R. Cooperstock, Smartphone sensor reliability for augmented reality (2013)
- A. Tartachynska, Yu. Pylypyak, smartphone compass accuracy against a theodolite (2026)
- GeoNames, cities with more than 15,000 people (CC BY 4.0)
- Wikidata (place names, CC0)
- OpenStreetMap contributors (Romanian locality positions, ODbL)
- Natural Earth, Admin 0 countries 1:50m
- Eurostat, population by country of birth / citizenship (cross-check)