Skyscrape rsweret heresulto f a needformore
workingand livi n gspaceIIIplaceswhereth e co stof
Lmdwasver ylu gh.Insteado f usltlg a lo tof
eXpe nSl\Tspan 'o n t hegroundrhcirb uildersusedthe
freespaceofth e sky.Newin dus t rialtech n iq ues , and
theavailabil it yofp lentyofc hca pst eel .madeit
possibleforthemtodot hi s.
Eachskys craperwasbuilr around aframeworkof
s tee lbeams.o r gi rde rs.whichcarriedtheweightof
th e b uilding.This inners te els ke leto nwas
constructedbeforet heouterwalls.whichwereadded
later.Thew allsofth eearlyskyscraperswereoften
made o fston ccno r for p ractical reasons ,b ut tomake
thebuildings looksolida nds t rong.
Int he1950sa rchitectswor k ingIIItheU n itedSt at es
begantodesig nskyscraperswhoses teelskeleton s
werecovere dbyouterwalls- o r"curtains'-ofglass
andm etal. On eoftheea rliestexampleswasMiesva n
dcrRohcandPh ilipJ o hn son 's SeagramB uildingin
N ewYork.ItwasA m ericanb u ildin gslikethisthat
ins p ired Similar"glassbox"off icean dapartmen t
buildingsIIIcinesallover t heworld.
Suchbuildi n gsgavevisual ex prl'SSlOll totheImpact
oftheU nite dStat esonrhet w enti e th-cen t u r y wo rld.
Theyweregleamingsymbolsofanamethatso me
historiansw e reg ivi ngtot he cent ur yevenbefore it
reacheditsend. Thenamew as" th eAmerican
CCIHury. "
33 T illA"IEIIIC.~NCE S TURY139