However, you shouldn't spend any diamonds on them, as better buildings will quickly appear (especially when you advance to the next era), making them obsolete.
http://forum3.bandingklub.cz/viewtopic.php?f=21&t=1596472
http://miweii.com/forum.php?mod=viewthread&tid=19258&extra=
https://ufr-2020.front5.picapo.net/forums/viewtopic.php?pid=553531
http://1.s.2.free.fr/viewtopic.php?f=2&t=308614
http://strada.bielsko.pl/1_lubelskie/forum/4-zadaj-pytanie/597396-casino-med-registreringsbonus-best-norsk-casino#597396
https://wietmarkt.nl/viewtopic.php?t=38429
https://www.ukalachat.net/forum/index.php?topic=8928.new#new
http://forum3.bandingklub.cz/viewtopic.php?f=18&t=1355942
http://forum.bandingklub.cz/viewtopic.php?f=48&t=1543740
http://forum.spolokmedikovke.sk/viewtopic.php?f=25&t=1137068&p=3985149#p3985149
