Answer based on context:

The Steelers returned home after a tough road loss to the Bengals to take on the Bears.  The first quarter was all Bears as they scored 17 unanswered points with Robbie Gould nailing a 47-yard field goal for a 3-0 lead followed up by Matt Forte's 5-yard touchdown run to make the score 10-0 and then Michael Bush's 1-yard touchdown run for a 17-0 lead.  The Steelers managed to get on the board in the 2nd quarter when Shaun Suisham nailed a 27-yard field goal to shorten the lead to 17-3, however the Bears increased their lead when Major Wright returned an interception 38 yards for a touchdown to make the score 24-3.  The Steelers came within 14 points at halftime as Ben Roetlisberger found Antonio Brown on a 33-yard touchdown pass to  shorten the score 24-10.  After the break, Gould kicked a 32-yard field goal increasing the Bears' lead to 27-10, but the Steelers answered with 13 straight points starting in the 3rd heading into the 4th quarter as Suisham nailed a 36-yard field goal for a 14-point deficit 27-13 and then a 21-yard pass to Brown from Roethlisberger again shortening the lead to 7 at 27-20.  In the 4th quarter, the Steelers came within 4 points as Suisham nailed a 44-yard field goal to make the score 27-23.  However, the Bears were able to seal the victory with Jay Cutler's 17-yard pass to Earl Bennett for a score of 34-23 and then Julius Peppers' 42-yard fumble return for a touchdown (with a failed PAT) for a final score of 40-23. With the loss, the Steelers dropped to 0-3 but on a positive note the team's 21-point deficit is the largest erased deficit in the franchise's history.  Though on the negative side the Browns won earlier in the day leaving the team in last in the AFC North.

How many yards was the longest touchdown?
42