LAKE FOREST, Ill. -- Chicago Mayor Lori Lightfoot revealed three proposals on Monday for renovations to Soldier Field to entice the Bears to remain at their home stadium of the past 50 years.

At the center of the proposal is the construction of a domed stadium, which could cost anywhere from $900 million to $2.2 billion.

Lightfoot laid out three options for construction of a dome:

• The first would fully enclose the stadium by rebuilding both end zones with columns that can support a dome structure.

• The second would require both end zones to be rebuilt with columns to make the stadium dome-ready.

• The third option calls for modifications to make Soldier Field a multipurpose stadium suited to host soccer games while also making it a viable location to accommodate major concerts and a range of events.

"An improved Soldier Field will deliver a world-class visitor experience," Lightfoot said in a statement. "Furthermore, any of these proposed renovations will allow Soldier Field to retain its role as an economic engine for Chicago for years to come, as these changes will allow us to keep bringing sports, music and other exciting events to our city."

The proposal also would expand seating at Soldier Field from 61,500 seats to 70,000, increase the number of suites from 133 to 140 and quadruple the food and beverage space from 50,000 square feet to 200,000 square feet. The statement also said the proposal would "dramatically expand the opportunity for major sponsorships and naming rights."

In September, the Bears took a step toward leaving historic Soldier Field when they signed a $197.2 million purchase and sale agreement with Churchill Downs Inc. for the 326-acre Arlington Park property in suburban Arlington Heights after the track, which has hosted thoroughbred racing since 1927, was put up for sale. The Arlington Park site, which is 30 miles northwest of Soldier Field, could be the site of a new stadium for the Bears in the future.

According to a statement released by the team earlier this month, the Arlington Park site is the only site the team is considering for a new stadium.

"As part of our mutual agreement with the seller of that property, we are not pursuing alternative stadium deals or sites, including renovations to Soldier Field, while we are under contract," the Bears said in a statement. "We have informed the City of Chicago that we intend to honor our contractual commitments as we continue our due diligence and predevelopment activities on the Arlington Heights property. In the meantime, we remain committed to fulfilling our Permit Operating Agreement (POA) at Soldier Field."

The Bears said Monday that they stood by their previous statement in response to Lightfoot's proposal.