请问参观梵蒂冈，背包里可以有水和吃的么？

It is not permitted to enter the Museums with alcoholic drinks. It is obligatory to leave alcoholic drink in the cloakroom before entering the Museums, these drinks must then be collected, on the same day, at the end of the visit. Visitors are allowed to leave food and drink in the cloakroom, on the condition that this is collected before closing hours. Uncollected food and drink will be destroyed at the end of the day.
入境随俗，正吃着让人家拍下来就又是中国人在博物馆如何如何的新闻了。进馆本来就要存包，建议别带包进去。

樓主指Vatican Museums嗎？見Food and drink─Visitors are allowed to leave food and drink in the cloakroom.http://mv.vatican.va/3_EN/pages/z-Info/MV_Info_Consigli.html

带不带进去看自觉，如果在里面吃喝还是不要给工作人员看到

没有人查，就没有问题；心诚则灵，洗刷灵魂，纯洁心灵

博物馆存包，进去的时候不要吃东西喝东西了。

没问题，工作人员亲口说矿泉水可以带进去的