Empress of Eternity by L.E. Modesitt, Jr. Library Call Number: PS3563.O264 E47 2010.
This challenging read begins with an enigma: from one end of the middle continent of Earth to the other, there is a canal that runs 2,000 miles, with a lighthouse or watchtower at its Western end. Civilizations rise and fall, but the canal remains, indestructible and indecipherable. Its creation apparently brought an end to one society—now three groups of scientists, separated by thousands of years, are studying it, all with their own planet-threatening situations. Each group begins to make discoveries, even as the group farthest into the future faces a religious war and a weapon of such power it might unravel the Universe. The lives of all of them, and the people of their times, depend on unlocking the secret of the Canal and Tower.