T4

A primary goal of the Nazi regime was to create a superior German race. In 1939 they began the secret T4 Euthanasia program designed to systematically murder all German infants, toddlers, and children up to age 17 who displayed or were diagnosed with ANY physical or mental disability. These children were seen as “useless eaters” and a financial burden to society. Initially, 10,000 children died by gassing, starvation, and lethal injection. These deaths were precursors to the killing operations that the Nazis instituted in order to kill over 11,000,000 people in the death, concentration, and slave labor camps. By war’s end over 250,000 disabled children and adults had also been murdered.

T4 was the code-name of the illicit program which came from the Berlin street address of the program's coordinating office: Tiergartenstrasse 4.

detail, T4 in progress

For further reading: https://www.jewishvirtuallibrary.org/background-and-overview-of-the-nazi-euthanasia-t-4-program