The same peninsula looks different depending whose map you open
Crimea has been administered by Russia since a 2014 annexation that most of the world doesn't recognize. Open a map of the region, and which country you're browsing from quietly decides what you see.
Fully integrated
Russian government maps show Crimea with the same solid, ordinary border as any other Russian region — nothing marks it as different or contested.
No border at all
Ukrainian maps draw no line separating Crimea from the rest of the country — it's simply Ukraine, the same as any other oblast, occupied or not.
Encircled, dashed
Most international map providers draw Crimea with a distinct dashed border — acknowledging Russia's on-the-ground control since 2014 without endorsing the annexation.
Russia annexed Crimea in March 2014, days after Russian forces took control of the peninsula and a disputed referendum was held under military occupation. The UN General Assembly responded with Resolution 68/262, affirming Ukraine's territorial integrity within its internationally recognized borders, including Crimea — and the vast majority of the world's governments still do not recognize the annexation as legitimate.
In practice, that leaves cartographers picking a side just by drawing a line. Russian state maps show no distinction at all. Ukrainian maps show no distinction either, just the opposite direction. Everyone else tends to split the difference with a dashed or dotted boundary — the standard cartographic signal for "administered by one party, claimed by another."
Sources: UN General Assembly Resolution 68/262 (2014); Russian Federal State Statistics Service regional listings; Ukrainian State Geocadastre. Country shapes: Natural Earth. Crimea boundary: geoBoundaries (Ukraine ADM1, "Autonomous Republic of Crimea" + "Sevastopol", dissolved and simplified).