▁ 1 6 7 3 ▁monument ▁to ▁Saint ▁E ul alia ▁in ▁Ped ró ▁Square . ▁ ▁Art works ▁are ▁typically ▁located ▁in ▁the ▁interior ▁of ▁nich es ▁and ▁on ▁the ▁fa ç ades ▁of ▁public ▁buildings . ▁They ▁are ▁concentr ated ▁because ▁of ▁the ▁city ' s ▁en closure ▁by ▁medieval ▁def ensive ▁walls . ▁The ▁walls ▁were ▁demol ished ▁in ▁the ▁ 1 9 th ▁Century , ▁spark ing ▁a ▁bo om ▁in ▁public ▁works ▁such ▁as ▁Il def ons ▁C erd à ' s ▁E ix ample ▁project . ▁ ▁The ▁city ▁an nex ed ▁several ▁municipal ities ▁in ▁the ▁early ▁ 2 0 th ▁century , ▁increasing ▁the ▁space ▁available ▁for ▁public ▁art . ▁Some ▁were ▁commission ed ▁for ▁particular ▁events ▁such ▁as ▁the ▁ 1 8 8 8 ▁and ▁ 1 9 2 9 ▁Ex pos itions , ▁the ▁ 1 9 9 2 ▁Summer ▁Olympics ▁and ▁the ▁ 2 0 0 4 ▁Universal ▁Forum ▁of ▁Cult ures . ▁ ▁Over view ▁▁ ▁Public ▁art ▁in ▁Barcelona ▁is ▁reg ulated ▁by ▁the ▁city ▁council ▁and ▁protected ▁by ▁Law ▁ 9 / 1 9 9 3 ▁of ▁Catal an ▁Cultural ▁Heritage , ▁which ▁guarante es ▁the ▁protection , ▁conservation ▁and ▁research ▁of ▁cultural ▁her itage ▁at ▁several ▁levels . ▁Public ▁monuments , ▁comm emor ating ▁historical ▁figures , ▁are ▁appropriate ▁for ▁a ▁large ▁city . ▁ ▁Urban ▁planning ▁includes ▁architecture , ▁engineering , ▁garden ing , ▁industrial ▁arts ▁and ▁sculpt ure . ▁Urban ism ▁rel ates ▁to ▁politics ,