A fire judged to be the most costly in the history of downtown Lawrence raged through three buildings at the south end of the 700 block between Massachusetts and Vermont, causing a loss estimated at well over $1 million. The Wren Building was one of the casualties. Three firemen were hurt fighting the early morning blaze in windy 12-degree weather. Other buildings affected by the fire were the Independent Laundry and Dry Cleaners, where the fire seemed to have started, and the Miller Furniture Co. at 741 Mass. Firefighters fought the blaze for more than five hours. The previous record fire loss here had been the $506,000 blaze in March of 1966 at the Rusty's Hillcrest supermarket.