What are some things the Harappan civilization excelled in?

These cities are well known for their impressive, organized and regular layout. They have well laid our plumbing and drainage system, including indoor toilets. Over one hundred other towns and villages also existed in this region. The Harappan people were literate and used the Dravidian language. Only part of this language has been deciphered today, leaving numerous questions about this civilization unanswered.