The Wikipedia page on the Russian banya mentions a curious comment attributed to none other than St. Andrew, the apostle. The page says that the comment was taken from the Primary Chronicle and it quotes directly from this English translation. Here I quote a bigger chunk, from the same source:

When Andrew was teaching in Sinope and came to Kherson (as has been recounted elsewhere), he observed that the mouth of the Dnieper was near by. Conceiving a desire to go to Rome, he thus journeyed to the mouth of the Dnieper. Thence he ascended the river, and by chance he halted beneath the hills upon the shore. Upon arising in the morning, he observed to the disciples who were with him, “See ye these hills? So shall the favor of God shine upon them that on this spot a great city shall arise, and God shall erect many churches therein.” He drew near the hills, and having blessed them, he set up a cross. After offering his prayer to God, he descended from the hill on which Kiev was subsequently built, and continued his journey up the Dnieper.

He then reached the Slavs at the point where Novgorod is now situated. He saw these people existing according to their customs, and on observing how they bathed and scrubbed themselves, he wondered at them. He want thence among the Varangians and came to Rome, where he recounted what he had learned and observed. “Wondrous to relate,” said he, “I saw the land of the Slavs, and while I was among them, I noticed their wooden bathhouses. They warm them to extreme heat, then undress, and after anointing themselves with an acid liquid, they take young branches and lash their bodies. They actually lash themselves so violently that they barely escape alive. Then they drench themselves with cold water, and thus are revived. They think nothing of doing this every day, and though tormented by none, they actually inflict such voluntary torture upon themselves. Indeed, they make of the act not a mere washing but a veritable torment.” When his hearers learned this fact, they marveled. But Andrew, after his stay in Rome, returned to Sinope.

This English translation was based on the Laurentian Codex (there are others). The original codex can be browsed online; here is a direct link to the image containing the passage. There is also an edition with the transcription of the whole codex here, created by Don Ostrowski. I now quote the same excerpt as above as it appears in his edition (from 7,25 through 9,4):

ѡньдрѣю оучащю въ синопии. и пришедшю ему1 в корсунь. оувидѣ ꙗко ис корсунѧ близь оустье днѣпрьское. въсхотѣ поити в римъ и проиде въ вустье днѣпрьское. ѿтоле поиде по днѣпру горѣ. и по приключаю. приде и ста подъ горами на березѣ. заоутра2 въставъ и реⷱ к сущимъ с нимъ ученикомъ. видите ли горꙑ сиꙗ. ꙗко на сихъ гораⷯ восиꙗеть блг҃дть бж҃ьꙗ. имать градъ великъ. и цр҃кви многи б︮ъ︯3 въздвигнути имать. въшедъ на горꙑ сиꙗ бл҃ви ꙗ. постави крⷭтъ и помоливъсѧ б︮у︯. и сълѣзъ съ горꙑ сеꙗ. идеже послѣже бꙑⷭ киевъ. и поиде по днѣпру горѣ. и приде въ словѣни. идеже нꙑнѣ новъгородъ. и видѣ ту люди сущаꙗ. како есть ѡбꙑчаи имъ. и како сѧ мꙑють хвощютсѧ. и оудивисѧ имъ. иде въ вариги и приде в римъ исповѣда елико наоучи. и елико видѣ. и реⷱ имъ дивно видѣхъ словѣеньскую землю. идучи ми сѣмо. видѣхъ бани древенꙑ. и пережьгуть е рамѧно. совлокутьсѧ и будуть нази. и ѡблѣютсѧ квасомъ оусниꙗнꙑⷨ ꙺ4. и возмуть на сѧ прутье младое. бьють сѧ сами. и тⷪго сѧ добьють. егда влѣзути ли живи. и ѡблѣютсѧ водою студеною. тако ѡжноуть. и то творѧть по всѧ д︮н︯и. не мучими никимже. но сами сѧ мучать. и то творѧть мовенье собѣ а не мученье. ты слꙹшаще5 дивлѧхуⷭ. ѡньдрѣи же. бꙑвъ в римѣ. приде в синофию.

A few comments are due. As far as I understand, Ostrowski’s edition attempts to closely follow the original codex, so I think there are at least two mistakes in his edition: he writes 1 емоу and 2 заутра, but I read ему and заоутра in the codex. I tried my best to reproduce the text using Unicode, but there are at least three problems I am aware of: 3 I think I used the right way to represent a titlo that spans multiple letters, but it doesn’t always display well; 4 I don’t know how to place multiple combining letters that are supposed to appear side by side, so I probably did it wrong; and 5 there’s no code point named combining cyrillic letter yeru with back yer, so I used combining cyrillic letter yeru instead.

The Laurentian Codex dates from 1377 and St. Andrew lived in the first century, so that the story is probably apocryphal. It’s a lot of fun, however, to find centuries-old remarks that are still valid today.