In the Vinony graph
Within Vinony's link graph, H21 is referenced by 1 other article, and connects out to Mata Hari and H-21 Shawnee.
It is catalogued under the topic Letter–number combination disambiguation pages.
Its subject is documented across 5 Wikipedia language editions.
~1 min read
Encyclopedic overview
H21 or H-21 may refer to: British NVC community H21, a type of heath community in the British National Vegetation Classification Highway H21 (Ukraine) , a Royal Navy H-class submarine , a Royal Navy S-class destroyer Mata Hari (1876–1917), German spy code named H-21 Piasecki H-21, an American helicopter Institute H21, a Czech think tank that created the website Prezident 21
Excerpted from Wikipedia’s “H21” article, available under the CC BY-SA 4.0 licence.