This is a very general question but the Germans during the Nazi period have contributed much to the world today as we know it.

Volkswagen, literally meaning the People's Car, was established as a car which would be available for the German people, like how the Ford Model T was viewed in the US. The Autobahn, the main highway system of Germany, was also developed during the time as well.

Germany's rocket program is the precursor to both the Soviet and US' space programs, which both have resulted in many advancements and innovations for the world. In fact after Nazi Germany was defeated most of the scientists of the German rocket program were secretly divided up by the USSR and the USA.

One can also argue that Nazi Germany and the horrors of World War II the modern world is the way it is today. The United Nations for instance, created during WWII by the Allied Nations, has been shaping the world as we know it since its inception.

There's a lot of answers to this question to be honest, I'll answer it in more detail later when I have more time.

This is quite a broad question, as there is an argument that everything revolutionary developed to aid the axis forces in the Second World War has, in some way, 'contributed' to the modern world. Keeping in mind 'contribute' can be a negative or a positive impact. Also keeping in mind that scientists inventing during the Third Reich weren't necessarily 'Nazis'.

Starting with a few inventions, the most notable of which being the perfection and mass production of the Turbojet engine, turbojets being used for almost all modern jet aircraft. Also noteworthy, the first Ballistic Missile. These paved the way for everything, from ICBMs to the space race, the things that made the Cold War so scary. Also, German scientists invented the fully synthetic opiate, Methadone, in 1937. There are plenty of examples of Nazi German inventions, such as the Jerry Can, Sarin gas, Neuclear research ,and Fanta.

The Nazis also lead numerous social and economic revolutions as well, many of which you still see today. Animal conservation (ie hunting laws), a ban on vivisection, the anti-smoking movement, and welfare for citizens (not so much Jews and Gypsies). The Autobahn is still the most striking Nazi infrastructure to, not only still exist, but to still greatly benefit modern Germany.

Then, of course, you have the negative contributions of the Nazis. Most notable being the extermination of around 6 million Jews, Gypsies, Disabled people and others not of 'Aryan Blood'. White supremacists, skinheads and other Nazi parties still live on in the memory of the Third Reich. Their influence caused the rapid militarisation of the two major superpowers of the mid twentieth century, and pitted them against each other, leading to everything occurring during the Cold War.