Complex sentence: Construction of the Cynwyd Heritage Trail officially began on Thursday, May 5,2011, when Lower Merion representatives symbolically broke ground for construction, although actual construction had already begun in March 2011 and volunteers had been maintaining the trail for many years.
Split into simpler sentences: Construction of the "Cynwyd Heritage Trail" officially began on Thursday, May 5th, 2011, when Lower Merion representatives symbolically broke ground for construction. Although, actual construction had already began in March, 2011 and volunteers had been maintaining the trail for many years.