The Altenburg is located in the Jenaer street which lies just outside of Weimar's city centre beyond the Ilm park. It was built in 1810-1811 and during the years following 1848, Princess Carolyne of Sayn Wittgenstein and her husband, Franz Liszt, lived there.
It took one year to build The Altenburg.
1810-1811 is one year so that is correct but the AI could not figure the math between the two years.
( z1 take :ARG0 ( z2 build :ARG1 ( z3 facility :name ( z4 name :op "Altenburg" ) ) ) :ARG1 ( z5 temporal-quantity :quant 1 :unit ( z6 year ) ) )