In Bereishis 1:9 it says וַיֹּאמֶר אֱלֹהִים יִקָּווּ הַמַּיִם מִתַּחַת הַשָּׁמַיִם אֶל מָקוֹם אֶחָד וְתֵרָאֶה הַיַּבָּשָׁה , And God said, "Let the water that is beneath the heavens gather into one ...
The Gemara says that King Hezekiah (Chizkiyahu) closed one of the springs of water in (under?) Jerusalem, so the Assyrian army wouldn't be able to use it. Do we have any guesses what exactly that ...
In high-altitude cities, water boils at a lower temperature than the standard 212 degrees Farenheit. For example, in Denver the boiling point is about 203 degrees. Can one kasher utensils with hagalah ...
Why is it called ירדן?