Right curly brace. It is the most powerful feature of C++.
I’m only half kidding, like I always am. Even now. Garbage collected languages have a big dumb machine following you around trying to figure out when you are done using the memory you allocated. When you think your code should be executing, the hulking monster you have no control over in your footsteps might decide it is time to take over the CPU.
As Bjarne Stroupstrup said, the best language for garbage collection is a language that doesn’t need it. C++ gives you control over the resources your program uses. I’ve never really understood RAII: Resource Acquisition Is Initialization. To me it is just a way of making C++ classes behave like built in types. Constructors do the dirty work of allocating memory and putting 0’s and 1’s in place, destructors undo that, copy construction duplicates the bits, and copy assignment clears out existing bits before duplicating the right hand side of operator=().
There are two new ways to help deal with C++’s propensity to create temporary objects, aka r-values, but this post is about l-value lifetimes.
An l-value is something that has a name for the memory associated with it. Maybe I should give mad props to left curly brace too. They introduce the scope that objects live in. Write the class and give it a name and the constructor brings it into existence. The right curly brace ensures the destructor gets called on the object.

It is all under your control in C++ if you just spend some time learning how it works.