much greater. here's david muir. >> reporter: behind these pillars at new york's main post office, towering need revealed through the words of children. >> one of the things we couldn't help but notice is the children aren't even asking for toys, many of them. they're just asking for clothing. >> the letters have changed. traditionally, it's been toys, me, me, me. now it's people asking for others. >> the basics. or for families. >> reporter: this letter from a 7-year-old. >> "this year i behaved good in school and my sister too. my mom doesn't have a job and my grandma buys everything. i only want clothes and shoes for me and my sister and our brother. thanks, santa, i love you. skayla." >> reporter: we discovered a sea of letters at post offices across this country. los angeles, 15,000 letters to santa. chicago, 7,200. and here in new york -- >> 2 million letters coming through here this year. >> this post office alone?