Hundreds of letters opposing the closure of Victorian baths in Nottingham were handed to the council.
The building is almost 150 years old
A rally was held in Nottingham's Market Square on Monday to mark the final day of a public consultation on the closure of the Victoria leisure centre.
Protest organisers said the letters, including some from children, asked the council to keep the baths open.
The city council said all views would be taken into account before a final decision was made.
Matt Anderson, of the Save The Victoria Baths campaign, said: "I hope the weight of our arguments will be enough to give them pause to reconsider and engage in a meaningful process whereby they can think about the various futures that the leisure centre can have."
The city council has said it would cost millions of pounds to renovate the leisure centre and would not be "value for money".
The authority said improvements to extend the pool and install a fitness suite would cost £7.5m.
Protestors said the closure would seriously affect residents of all ages in the area who need good local recreation facilities.
A final decision on the plans will be made on 18 March.