Mientras + Subjunctive

[fglorca]

Does 'mientras' always take a subjunctive if we are referring to something in the future?

Example:
I'm going to Spain next week; while I'm there, I will spend lots of money.
Voy a Espana la semana que viene, mientras 'esté' allí, gastaré mucho dinero.

[Rusty]

Yes.I'm going to Spain next week. While I'm there, I will spend lots of money.
Voy a España la semana que viene. Mientras esté allí, gastaré mucho dinero.