Long before it was called India's Silicon Valley, Bengaluru was known as the Garden City, thanks to Lalbagh, Cubbon Park and its tree-lined avenues of rain trees, gulmohars and jacarandas. Its mild climate also made it a favourite place for retired civil servants and military officers, hence the nickname Pensioners' Paradise.
The city's tree cover has shrunk a great deal as it has grown, but Lalbagh's flower shows on Republic Day and Independence Day still draw huge crowds. See Lalbagh and Cubbon Park.
Further reading: Lal Bagh on Wikipedia.