chock-a-block /ˌtʃɒk ə ˈblɒk◂ $ ˈtʃɑːk ə ˌblɑːk/ BrE AmE adjective [not before noun] British English
[ Date: 1800-1900 ; Origin: chock-a-block 'with the wooden blocks of a tackle (= ropes for lifting) touching each other, so that no more can be lifted' (1800-1900) , from chock on block ; influenced by chock-full ]
completely full of people or things
chock-a-block with
Paris was chock-a-block with tourists.