<s>
Dragon	B-Application
City	I-Application
is	O
a	O
free-to-play	O
social	O
network	O
game	O
developed	O
and	O
published	O
by	O
Socialpoint	O
.	O
</s>
<s>
Dragon	B-Application
City	I-Application
tasks	O
players	O
to	O
raise	O
their	O
dragons	O
and	O
design	O
a	O
city	O
full	O
of	O
dragons	O
on	O
floating	O
islands	O
.	O
</s>
<s>
Once	O
a	O
player	O
has	O
reached	O
Level	O
27	O
,	O
the	O
Ancient	O
World	O
can	O
be	O
accessed	O
,	O
which	O
is	O
an	O
area	O
of	O
the	O
game	O
where	O
Gold	O
can	O
be	O
exchanged	O
for	O
Crystals	O
(	O
ruby	B-Language
,	O
sapphire	B-Application
,	O
topaz	O
,	O
emerald	B-Language
,	O
onyx	O
,	O
and	O
diamond	O
)	O
which	O
can	O
be	O
collected	O
from	O
mines	O
that	O
can	O
be	O
used	O
to	O
summon	O
and	O
evolve	O
Ancient	O
Dragons	O
.	O
</s>
<s>
Dragon	B-Application
City	I-Application
was	O
first	O
released	O
in	O
Facebook	B-Application
in	O
May	O
2012	O
,	O
with	O
iOS	B-Application
and	O
Android	B-Application
in	O
2013	O
.	O
</s>
<s>
On	O
February	O
26	O
,	O
2019	O
,	O
the	O
Microsoft	B-Application
Windows	I-Application
version	O
of	O
the	O
game	O
was	O
released	O
.	O
</s>
<s>
On	O
February	O
2	O
,	O
2020	O
,	O
the	B-Application
Facebook	I-Application
version	O
of	O
the	O
game	O
was	O
closed	O
.	O
</s>
