By 2500 BCE, what did the Harappan civilization develop that would not be seen again for 3,000 years?

Indoor bathrooms

Explanation:

Based on the sites that left over by this civilization, Archologies noticed that   there are rooms that were most likely used for indoor bath.  Not all building continued these bathrooms. Archeologists believed that it's only common among the upper class members of Harrapan civilization.

Judging from the size of the bathrooms, it is unlikely that they're used for personal bath. It's more suitable for some sort of group setting like for courtesans to entertain a noble. This type of bathrooms did not exist in other civilizations in that era. The closest ones found in Roman empire in around 390 AD.

world war i had a devastating effect on german-americans and their cultural heritage. up until that point   german-americans, as a group, had been spared much of the discrimination, abuse, rejection, collective mistrust experienced by so many different racial and ethnic groups in the history of the united states. indeed, over the years, they had been viewed as a well integrated and esteemed part of american society. all of this change with the outbreak of war.  

there are indirect ways of affecting state laws   by with holding funding's. and that's why we have a 55mph speed on the high way with a design of 70mph speed.