The Mormon Church believes that we can perform ordinances such as baptisms, marriages (sealings) and Endowments for those people that are dead. These rites are performed in Mormon Temples
There are about 150 temples worldwide. They are beautiful, massive buildings that are constructed with the finest materials and engineering. Their cost has to be enormous. (The church does not release the cost of anything.
|The San Diego Temple|
|Baptismal Font inside a temple|
Even though the LDS Church has at times performed temple ceremonies in rivers, tents and cabins, they insist on building $50 million ornate buildings while knowing of the suffering, hunger and poverty around the world.
It is a common story taught in LDS churches of a poor family from an island in the Pacific or somewhere deep in the Amazon saves money for years to attend the temple at a distant location rather than use the money for education or housing. The story refers to the great sacrifice and faith of those people, essentially promising them eternity in Heaven.
The real cost of all this might be in the shaming and social loss of those who leave the faith or part member families who cannot attend the temples weddings of their loved ones.
List of LDS Temples - Wikipedia
Social Cost of Temples Attendance
LDS.org - Why Temples?