Massive crowds, estimated at more than a million people, swarmed every imaginable viewing spot along Boston Harbor — from Seaport to downtown, from Charlestown to East Boston — for the arrival of more than 50 tall ships and military vessels, representing more than 20 countries, as part of the Sail250 celebration. It’s the first time Boston has hosted a tall ships event since 2017. Click the link in our bio to read how the day unfolded. Video by Alex Pickering for The Boston Globe. Edited by Anus