In this picture taken on Saturday, Oct. 27, 2018 people walk between the paths during the unveiling of the 'Tree Library' park, in Milan, Italy. If Italy's fashion capital has a predominant color, it is gray not only because of the blocks of uninterrupted neoclassical stone buildings for which the city is celebrated, but also due to the often-gray sky that traps in pollution. The city has ambitious plans to plant 3 million new trees by 2030_ a move that experts say could offer relief to the city's muggy and sometimes tropical weather. (AP Photo/Luca Bruno)