Куда бы я ни поехал, море остаётся в моей памяти.

Куда бы … ни is a “free-choice / no-matter-where” construction: wherever / no matter where.

• бы (the conditional/subjunctive particle) helps create a non-specific, hypothetical range of possibilities: “wherever I might go.”
• ни reinforces the idea of “it doesn’t matter which one” (often called “concessive” ни): “no matter where.”
  Together, куда бы я ни поехал ≈ “wherever I go / wherever I may go.”

Because the first part (Куда бы я ни поехал) is a subordinate clause, and the second part (море остаётся…) is the main clause. Russian normally separates subordinate clauses with a comma.

In this construction, Russian uses the past-form of a perfective verb with бы to express a hypothetical action, not actual past time.
So я поехал бы literally looks like “I would go,” and in куда бы я ни поехал it becomes “wherever I may go / might go.”

поехать (perfective) focuses on the single event of setting off / going (once) to some destination—appropriate for “no matter where I go (as a trip).”
ехать (imperfective) would emphasize the process of travelling/driving, and it’s less natural in this fixed pattern.

They’re close, but not identical in style/nuance.

• Куда бы я ни поехал = “wherever I might go” (more hypothetical/“no matter where I end up going”).
• Куда я ни поеду = “wherever I go (in the future)” (more direct future sense).
  Both can work; the бы version often feels more literary or reflective.

The common neutral order is Куда бы я ни поехал.
ни typically stands right before the verb (or the stressed element), and that position is strongly preferred. You might see small variations in literature, but as a learner it’s best to keep …я ни + verb.

Russian present tense is often used for general truths / habitual facts. Here it means: regardless of future travel, “the sea remains in my memory” as a constant.

в + location/“in” meaning takes the prepositional case.

• память → в памяти
• моя agrees in case, gender, number: в моей памяти
  It means “in my memory,” i.e., as something preserved mentally.

ё marks the stressed sound yo: остаётся (stress on ё).
In many texts, ё is often replaced with е (so you may see остается), but pronunciation is still остаётся. Keeping ё is clearer for learners.

Yes. In море остаётся в моей памяти, the subject is море (“the sea”), so it’s in the nominative case. The verb остаётся agrees with it in number (singular).

Yes, that’s grammatically possible. The comma remains.
The original order foregrounds the “wherever I go” condition; the reversed order foregrounds the main idea first (“The sea stays in my memory…”).

Yes—Russian has a whole set of “no matter…” patterns:

• где бы … ни = no matter where
• когда бы … ни = no matter when
• что бы … ни = no matter what
• как бы … ни = no matter how
• сколько бы … ни = no matter how much/how many
  They work similarly: question word + бы + … + ни + verb.