An estimated 1.2 million people linked hands in a human chain the length of the island Saturday as President Chen Shui-bian (search) urged protesters to oppose China's military threats and create the "Great Wall of Taiwan's democracy."

The event was the biggest islandwide demonstration in Taiwan's history. The protesters hoped it would win the world's sympathy for Taiwan in its struggle against China. But it could end up further antagonizing the communist giant.

The people-power display was also designed to give Chen a boost in the tight race ahead of the March 20 presidential election. Opposition parties refused to join the human chain. They held rival events, including a blood drive and a torch relay.

Chinese leaders insist self-ruled Taiwan belongs to China, and they have repeatedly threatened to use force to take over the island, 100 miles off the mainland. China's massive military has nearly 500 short-range missiles pointed at Taiwan.

Kicking off Saturday's event in the western county of Miaoli, Chen told supporters, "Everyone should hold hands and protect Taiwan's national sovereignty, democratic development, economic prosperity and permanent peace in the Taiwan Strait."

As people in the human chain cheered, Chen said, "I am very happy that together we can write history. This is the Great Wall of Taiwan's democracy."

Organizers said more than a million people formed the human chain that stretched 303 miles — from the northern port of Keelung down the flat western coast to Pingtung County near the island's southern tip. Local TV stations that covered the event from helicopters said the chain was complete.

In the capital, Taipei, people linked hands in front of the red brick Presidential Office. They raised their hands in the air, shouted "Taiwan Yes!" and released heart-shaped balloons into the air as cars passed by and honked their horns in support.

Retired dentist Wayne Wu, 68, said the event was successful. "It was peaceful, short, and clear," he said. "This was history, and I wanted to be part of it because I am Taiwanese. I am not Chinese."

Standing nearby, accounting student Lisa Lu, 22, hoped the protest would send a message to China.

"This is the best chance we have to tell China what the people of Taiwan think," she said. "This is not only the politicians talking. This is the whole people."

Ronald Wang, a 42-year-old engineer, added, "We must show China this is our country. They have no right to tell us what to do. Today, the whole world will understand."

The president also used the protest to remind voters to cast ballots in Taiwan's first islandwide referendum, to be held on the same day as the presidential election.

Voters will be asked whether Taiwan should increase anti-missile defenses if China refuses to withdraw the missiles it has pointed at the island. The referendum will also ask voters if Taiwan should hold talks with China to normalize relations.

Beijing has criticized the referendum. Chinese leaders worry it could set a precedent for a referendum on the touchy unification issue.

The organizers chose Feb. 28 for the human chain to mark the anniversary of an uprising in 1947, known as the "228 Incident," when anti-corruption protests turned violent. Soldiers with the former Nationalist government put down the demonstrations, killing hundreds, maybe thousands, of people.