The Kingdom of Saudi Arabia recently announced plans to expand the Haram Mosque in Mecca - Islam’s holiest city - to accommodate the ever increasing number of pilgrims during the Hajj; a duty, if possible, of all Muslims.

Every year during the Hajj, thousands of images show millions of Muslims circle the Ka’ba, which the Haram Mosque is built around. And every year is it clear that despite its grand size - the Mosque currently holds 900,000 worshipers - the Mosque is overflowing with worshipers attending to their prayers in the streets of Mecca.

The Haram Mosque is overflowing because given the steep drop in air travel and the emergence of a global middle class in the developing world - where most Muslims live - more and more Muslims and afford to go to Mecca. The Saudi’s now have a plan to accommodate.

The Kingdom has announced a two-phase plan that will first increase the Mosque to a capacity of 1.5 million and then 3 million. This will mean that the Haram Mosque will almost be built anew.

For the job - which will easily be one of the 21th centuries more important - the Saudis have contracted the Baghdad-born British architect Zaha Hadid and her co-patriot Lord Foster. This choice is not without controversy.

Hadid is a Muslim, but Lord Foster is not. It is ironic that the Saudis, who preach such a xenophobic ideology toward Jews and Christians, would choose a Christian English man to aid the design of the most important Mosque in Islam. But the objection to Lord Foster is not necessarily rooted in any xenophobia.

Many tolerant Muslim are opposed to a non-Muslim having anything to do with the architecture of such a prominent Mosque. Catholics, for instance, might likewise find objectionable efforts by Muslims to have a say in redesigning, say, the Vatican. Theological matters aside, Lord Foster will have to do his part without actually visiting Mecca.

The city, along with Medina, is off-limits to non-Muslims. Given the grandeur scale envisioned it seems impractical that Lord Foster would be able to properly image a new grand Mosque if he cannot be on site. The accompanying Zaha Hadid and panoramic photos and videos will be his only guide to Mecca.

Further, Muslim or non-Muslim, Lord Foster and Ms. Hadid will both confront a mandate that they are foreigner to: classical architecture. Lord Foster and Hadid both made their names in modern architecture, though fitting in New York or London, abstract architecture if not most appropriate for the Haram Mosque.

A structure large enough to hold 3 million people, especially wide-based, is bound to take up enormous space. That has some Saudis worried. Sami Angawi, himself a Saudi architect, is the founding-director of the Haj Research Center. HRC is dedicated to preserving historic sites in Mecca.

Numerous structures of Islam’s early history have been bulldozed over by the five-star hotels like the Hilton and and Starbucks that surround the Haram Mosque. The presence of such lavish hotels is a criticism that many Muslims have toward the Saudi handling of the Hajj, many Muslims accuse the Saudis of not seeing the duty as a solemn obligation, but, rather, as a way to squeeze money from pilgrims.

Mr. Angawi worries that the Mosque expansion will lead to even more bulldozing. Unfortunately for Mr. Angawi, the Saudi monarch does not share his concern. The radical Wahhabi Islam that is state ideology in Saudi Arabia views efforts to preserve historical sites to be a facet of idolatry. Thus they are indifferent to the fact that both the house of the Prophet Muhammad’s first wife, Khadiji, and the school where Prophet Muhammad taught have both been destroyed.

No date has yet been set for the completion of the first phase, or even when Hadid and Lord Foster will unveil their design.