Although the opening of the sea routes from Europe to the East was partly responsible for the decline of certain routes (such as the great Silk Road from China to the Mediterranean), several important caravan routes yet flourished until the 19th century, when road and rail transport and the abolition of the slave trade resulted largely in their demise. Some local caravans still survive in the absence of alternative transport, and certain others because of some particular appeal or advantage. Some of the Muslim pilgrim caravans continue, for example, because it is regarded as more meritorious to travel the hard traditional route