budapest history

i have read some interesting stories about the history of budapest.
in the 1870s there were lot of debates about the rapid construction of the city. in just 50 years budapest has its size, and there were some futuristic plans. the surroundings of the former city of pest, the 6th, 7th, 8th, 9th districts was mainly swampland with smaller rivers. where today there is the big boulevard, there was also a small river and they wanted to create a shippable channel. why they have rejected this plan was the reason, that all the waste water would so swim in the city, which would be anti hygienic. still now waste water is a problem: the bulk of it is just flooding into the danube, without cleaning. there is a project ongoing, which will be finished in the next years to clean every waste water. so till that point never swim in this river!
in ww2 the front line was in the city between the germans and sowiets. in the bombings and in the fights the animals escaped from the zoo (which belongs to the oldest ones in the world). one lion lived in daytime in the subway, and was attacking people in the night. but as almost all animals died, they have asked the sowiet army not to shoot it, and they really have managed to catch it in the tunnel.