Build a masjid in this world and build your palace in Jannah

The masjid is the heart of any Muslim community. Providing much more than a place of worship, many offer education and are a base from which essential community services are delivered.

He said, ‘Whosoever builds a house (masjid) for the pleasure of Allah, whether it be small or large, Allah builds for him a house in Paradise.’
– at-Tirmidhi, Ibn Khuzaymah, Ibn Hibban

It is an excellent form of Sadaqah Jariyah as the donor can expect to receive rewards as long as people worship there.