The United Nations is considering which new sites should be added to its World Heritage List.
Bam is thought likely to be added to the Heritage list
The 48 proposals include what could become North Korea's first entry on the list - a complex of dynastic tombs.
Unesco, the UN's cultural body, is also discussing how to protect its existing sites at its annual meeting in the ancient Chinese city of Suzhou.
A top Unesco official said development posed an even bigger threat to world heritage than war or natural disaster.
"What is most important at the moment is the very, very big urban development... which in many cases is made without proper respect for historical sites," said Mounir Bouchnaki, assistant director general of Unesco.
In a nod to the conference hosts, he said China faced an especially serious challenge because of the construction accompanying its rapid development.
One of the sites thought likely to be placed on the list of culturally or naturally important places this year is the Iranian city of Bam.
Its mud-brick fortresses survived for hundreds of years until an earthquake in December last year all but destroyed the city, and killed an estimated 26,000 people.
But Unesco has warned that another of Iran's ancient sites, the city of Isfahan, could be removed from the World Heritage list and branded "world heritage in danger" because of "uncontrolled urbanisation".
Rampant urbanisation may threaten Isfahan's status
Media in South Korea - which has seven World Heritage sites - have also been touting their northern neighbour's chances of getting its first.
North Korea and China are making a joint presentation on behalf of a series of tombs that straddle their border, dating from the Koguryo dynasty, which reigned from 277 BC to 668 AD.
North Korea applied to have the site recognised last year, but was turned down.
Unesco would not release the full list of 48 sites - saying the successful applicants would be named over the course of the conference, which lasts until 7 July.
A spokesman said there would be a lot of political to-ing and fro-ing before the decisions were announced.
"They are trying to limit the number of new sites," he told BBC News Online.
"In theory there should be a maximum of 30, but we'll have to see if they stick to that or go beyond it.
"There are a lot of different criteria which come into play."