HOUSTON -- Hundreds of residents of a center for mentally retarded people rallied at Houston City Hall Tuesday in an effort to save their home, KPRC Local 2 reported.

The Center Serving Persons with Mental Retardation occupies 6 acres of prime real estate near downtown Houston and pays the city $1 a year under a 99-year lease signed in 1963.

City attorneys argue the center's lease is invalid under the city charter, which limits leases to no more than 30 years. City officials want the lucrative property developed to generate more revenue.

Nearly 200 people, most with disabilities, rode chartered buses to City Hall for the demonstration.

The staff worked with the special needs residents for several days to prepare them for the field trip. Any break in routine could potentially upset the residents, officials said.

"I hope today that the mayor will see the emotional and the face to this problem -- the people that will be displaced -- the families that depend on this inner-city center," said Terri Schwartz, a family member of a disabled resident.

"There are about 200 that live here, but there are 300 to 400 that come in from their homes -- their group homes or they may be living with their families and they have jobs here," said Alison Bailey, a family member of a disabled resident. "I'm hoping they'll see the heart, and the caring is more important than the dollar."

Dozens of residents and staff members' families rallied on the steps of City Hall.

"We are simply hoping and praying that our presence will touch the hearts of those making decisions on our behalf," a center employee said to the crowd.

Inside City Hall, Houston Mayor Bill White told a packed audience that he would take as much time as needed to work out a fair resolution with the nonprofit group.

The mayor's words calmed the crowd because much has been made about a letter from the city that threatened the immediate sale of the property if the board for the center refused to negotiate the lease, KPRC reported.

By one broker's estimate, the tract is worth as much as $26 million.

The center said it provides education and training to about 700 people daily. Services also include mental and dental care along with speech therapy and counseling.