Well London already has its fair share of wonders, but another good local one that should be in the game is the Crystal Palace:-
Originally built to house the Great Exhibition of 1851 in Hyde Park, it was relocated to South London, where it stood until it sadly burned to the ground in 1934. A true marvel of Industrial Era engineering, it was three times the size of St Paul's Cathedral, its construction aided by novel manufacturing techniques to mass-produce cheap strong sheets of glass.
Spoiler The Crystal Palace :
Originally built to house the Great Exhibition of 1851 in Hyde Park, it was relocated to South London, where it stood until it sadly burned to the ground in 1934. A true marvel of Industrial Era engineering, it was three times the size of St Paul's Cathedral, its construction aided by novel manufacturing techniques to mass-produce cheap strong sheets of glass.