Making the world better, one answer at a time. The primary germ layers (endoderm, mesoderm, and ectoderm) are formed and organized in their proper locations during gastrulation. Endoderm, the most internal germ layer, forms the lining of the gut and other internal organs. Ectoderm, the most exterior germ layer, forms skin, brain, the nervous system, and other external tissues. Mesoderm, the the middle germ layer, forms muscle, the skeletal system, and the circulatory system.
Eiffel Tower. The Eiffel Tower, located in Champ de Mars in Paris, is a tall wrought-iron structure made by man. It is one of the most famous monuments of the world. It is the most famous landmark of Europe, held the record as the tallest man-made structure of the world from 1889 to 1930 with its height of 324 meters.
The construction of the Eiffel tower. Eiffel Tower. Work began in January 26th, 1887 with the digging of the Tower's foundations, which were laid in four months. The work started on July 1st, 1887 to end twenty-one months later. All the elements were prepared in Eiffelâs factory in Levallois-Perret, on the outskirts of Paris. Each of the 18,000 pieces used to construct the Tower was specifically designed and calculated, traced out to an accuracy of a tenth of a millimetre and then put together to form new pieces, each measuring around five metres.