The Leaning Tower of Pisa Has Never Been Straight

Soon after building started in 1173, the foundation of the Pisa tower settled unevenly. Construction (1)_____, and was continued only a 100 year later. It then became visibly clear that the Tower of Pisa is leaning, tilting to the south.

Since regular measuring of the tower began in 1911, the top of the tower (2)_____ 1,2 millimeters per year. In 1989, the Tower of Pisa Project Consortium commissioned engineers (3)_____ the Leaning Tower. Because the Tower tilted in different directions in its first years, it is slightly curved, like a banana. Engineers are working on the footing of the Tower rather than the structure, (4)_____ to ease the top back about 20 cm. But it means that (5)_____ tower will remain leaning.

The Swiftly Evolving Blackcap

Evolution doesn’t have to take centuries. In the case of the Blackcap songbird, (6)_____ decades were enough. The birds breed in the forests of southern Germany, and traditionally fly to Spain for the winter. Most still make the journey south, but since the 1960s, 10% (7)_____ to wintering in England, where the colder climate is more than (8)_____ by the food left out on bird tables - a postwar phenomenon. These birds have rounder wings than their Spanish cousins (which provide better mobility but are (9)_____ suited to long-distance flight) and longer, narrower beaks, better suited to bread and nuts than to olives. Researchers speculate that if the birds (10)_____ to evolve in this way, they could eventually become a distinct species.