Learn Spanish (Latin America): El recuerdo de lo que vivimos me da mucha nostalgia. - The memory of what we lived gives me a lot of nostalgia.

Memoria usually refers to your brain's capacity to remember things, similar to a computer's memory. When you are talking about a specific recollection of a past event, person, or time, you use recuerdo.

Why do we need "lo que" instead of just "que" or "qué"?

Lo que means "that which" or "the things that" when referring to an abstract idea or situation that hasn't been specifically named. You can't use qué with an accent because it isn't a question or exclamation here, and a simple que (that) wouldn't make sense. Lo que vivimos translates perfectly to "what we experienced."

Is "vivimos" in the present or past tense in this sentence?

It is in the preterite (past) tense. For regular -ir verbs like vivir, the nosotros (we) form is identical in both the present and the preterite. You have to rely on context to tell them apart. Since the sentence is about a memory (el recuerdo), we know they are talking about the past.

Why does the sentence say the memory "gives me" (me da) nostalgia instead of "makes me" nostalgic?