PUERTO PRINCESA CITY, Philippines -- The Puerto Princesa Subterranean River National Park, the country's single remaining entry to a Web-based voting for the seven new natural wonders of the world, has made it to the semifinal round of the ongoing selection process.

The organizer of the campaign, the Switzerland-based New7Wonders Foundation, announced Thursday the 77 semifinal winners which made it to the penultimate round of selection following a year of email-based voting where over one billion votes were cast over the Internet with the Philippine's lone entry making the cut.

Based on the predetermined process of selection, an international panel of experts will evaluate the remaining 77 sites and will select the 28 finalists to be announced on July 21 based on a set of criteria determined by the organizers.

A final round of Internet voting will then be held for another year until the seven winners are determined and declared in 2011.

Puerto Princesa City Mayor Edward S. Hagedorn said the city government, which has launched a full-blown campaign to solicit votes for the country's lone entry, was confident the subterranean river would make it to the list of 28 finalists.

"I'm really pleased that we made it this far, even with little support from the national government, considering that we were competing with entries like the Amazon, which is being supported by at least five countries," Hagedorn said.

Puerto Princesa's underground river, a cave complex that features a two-kilometer navigable route underneath a limestone formation, has attracted hundreds of thousands of local and foreign visitors, particularly during the last two years after it was first nominated as one of the country's several entries in the global voting campaign.

The underground river topped the first phase of the selection process during the first year of the campaign, which involved over 400 entries from all over the globe, leading other previous Philippine nominees including the Tubbataha Reefs, Bohol's Chocolate Hills, Mayon Volcano and several other entries.

Also making the top 77 entries are popular natural attractions such as Australia's Great Barrier Reefs, Brazil's Amazon Forest, the Grand Canyon in the United States, and Mt. Olympus in Greece, among others.

Organizers, however, noted that the semifinal has included many places that are less known to the public.

The organizers explained that the criteria for final selection will include: unique beauty of the nominated site; diversity and distribution across and among the different site categories, including landscapes, ice formations, islands, mountains, volcanoes, caves, rock formations, valleys, forests, national parks, nature reserves, lakes, rivers, waterfalls, seascapes; ecological significance (both as ecosystems and/or in their significance for humans); historical legacy (relations that humans have or have had with the site); geo-location (even distribution of the 28 official finalists between continents and countries).

The 28 finalists will be announced in Zurich at the New7Wonders Foundation headquarters on July 21. Votes are cast on this website: www.new7wonders.com.