WhileIwentsightseeinginLondonIvisitedtheLondonUnderground.LikemosttouristsIwasveryinterestedinitasitisthe 61 (old)systemintheworld.Itisalsoverycomplex.Iwastoldthatthefirstpartoftheundergroundsystemopenedin1863and 62 tookpeoplefromtheboundaryofLondontothecitycenter.Theundergroundpassageswereverynarrow 63 (compare)tothelastlinethatwasconstructedin1977.when 64(carriage)firstraninthesepassagestherewaslots 65 smokeandnoise.Ithinkitmusthavebeenhorribleanddampdownthere!Anotherproblemwasthattherewereadozendifferentlines 66 werenotlinked.This 67(make)thesystemnotuser-friendlybutnowthedifferentlineshavebeenjoined.TheunionofthedifferentlinesmakestravelingontheLondonUndergroundmuchmore 68 (convenience).Iboughtaticketatadiscountandrodetheundergroundthreetimes.Itwasgoodforme 69 (have)theexperience.AnotherinterestingthingwasthatthepassagewereusedforallsortsofthingsduringWorldWarIIsuchasbombsheltersandananti-aircraftcentre.It’s 70 (true)amazing!