Linked from
The 28 pages that link to Sumatra, each with the reason it gives.
Java SeaRelated: Its eastern shores help enclose the sea's western reaches.
Sumatran tigerRelated: This island is the Sumatran tiger’s native range.
Rafflesia arnoldiiRelated: The species is native to Sumatra’s rainforests.
Sunda clouded leopardRelated: It is one of the two islands where Sunda clouded leopards live.
CilegonRelated: Cilegon’s Merak ferries connect Java with Sumatra’s Bakauheni terminal.
PangkalpinangRelated: Sumatra is Bangka's nearest major landmass and a key regional connection.