Everything you need to know about the 'incredible' logistics of Indonesia's presidential election

Over land, across seas, through the air and even being dragged by a cow — these are just some of the ways that ballot papers and boxes will reach polling stations in Indonesia's astonishing one-day election. 

Nearly 205 million people are registered to vote on Wednesday, as the world's third-biggest democracy decides on a new president. 

Serving these voters will be more than 800,000 polling stations, spread across this archipelago of some 17,000 islands. 

It's a logistical challenge, which is made even more difficult by unpredictable events in the run-up to polling day. 

"Some of the challenging aspects in managing election logistics include limited time, extreme weather, geographical conditions and even security disturbances," said Yulianto Sudrajat, head of the planning and logistics division at Indonesia's general elections commission. 

Elections officials in central Java have already postponed voting in 10 villages due to floods, with more warnings of potential disruption in the west of the island on election day. 

Voters are deciding on a replacement for outgoing President Joko Widodo, with Defence Minister Prabowo Subianto the current frontrunner. 

Subianto is head of the populist Gerindra party. He has pledged to continue with many of the outgoing president's major policies and is running alongside Widodo's son, Gibran. 

The candidate for the ruling Indonesian Democratic Party of Struggle is former Central Java governor Ganjar Pranowo. He has campaigned as a man of the people, but Widodo decided against backing him. 

The third candidate is Anies Baswedan, who is running as an independent. Unlike Subianto and Pranowo, Baswedan has pledged to move away from Widodo's flagship policies, including the decision to move the country's capital away from Jakarta. 

Presidents are elected for a five-year term but can only rule a maximum of two terms. 

Indonesians will also elect a new vice-president as well as parliamentary and local representatives. 

Security officials will likely be on high alert on Wednesday, following unrest after the last presidential election in 2019. 

Protesters took to the streets and clashed with police after official results showed that Widodo had secured a second term as president. Eight people were killed in the violence in Indonesia's capital.