With no explanation, label each line with "location-GPE", "O", "other-award", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
The
United
States
historic
district
,
a
single
listing
on
the
U.S.
National
Register
of
Historic
Places
,
was
designated
in
1966
.
The:O
United:location-GPE
States:location-GPE
historic:O
district:O
,:O
a:O
single:O
listing:O
on:O
the:O
U.S.:other-award
National:other-award
Register:other-award
of:other-award
Historic:other-award
Places:other-award
,:O
was:O
designated:O
in:O
1966:O
.:O