Mont Blanc massif led to calls to limit access to the most popular summits and for the mountains to be treated with greater respect. The Mont Blanc massif has provided numerous opportunities for academic research, dating back to the very first ascent of Mont Blanc in 1786 during which Michel Paccard carried scientific equipment to confirm it as the highest summit. In 1820, an ill-fated expedition led by Dr Hamel included pigeons intended for release at varying altitudes to measure the impact of reduced air density on their ability to fly. In 1890, Joseph Vallot built a small meteorological observatory at approximately between
4th Summit of the Americas put pressure on the European Union to cut its farm subsidies, a major issue in world trade negotiations. In the midst of protests from the civilian population and after US refusal to end or reduce his protectionism on agricultural markets, and opposition from the four Mercosur countries (Brazil, Argentina, Uruguay, and Paraguay) and Venezuela, which maintained that the U.S.-led proposal would damage their nations' economies, the Summit talks failed to reach an agreement on a regional trade deal. Talks continued beyond the scheduled end of the meeting as supporters of the U.S.-led proposal sought to set another date to continue