The idea first surfaced in 1960, when Professor Sedyatmo of the Institut Teknologi Bandung proposed connecting Sumatra, Java, and Bali as part of a grand vision called Tri Nusa Bimasakti. For decades the concept remained just that -- a concept mentioned by academics and politicians from time to time, never advancing past conversation. Then in 2007, the Indonesian government gave an initial green light. The plan called for a series of suspension bridges carrying a six-lane highway and double-track railway across three small islands in the strait: Prajurit, Sangiang, and Ular. The upper span of 3,300 meters would rival Italy's planned Messina Strait Bridge; the lower span of 1,991 meters would match Japan's Akashi Kaikyo Bridge. Cost estimates started at ten billion dollars and quickly climbed to twenty billion. If built, it would be the most expensive infrastructure project in Indonesian history.

Engineering ambition is one thing. Geography is another. The Sunda Strait sits near the Sunda Trench, one of the planet's most active seismic zones, shaken regularly by significant tremors. Forty kilometers from the proposed bridge route lies Krakatoa, whose catastrophic 1883 eruption killed tens of thousands and reshaped coastlines across the region. Any bridge here must withstand not only earthquakes but the possibility of volcanic activity and tsunamis. The strait's seabed contours, geological faults, and volcanic geology all demanded study before a single pylon could be placed. Meanwhile, the bridge would need to allow passage for the largest vessels afloat, including container ships and even aircraft carriers, on a sea lane where east-west domestic ferry traffic crosses north-south international shipping routes. Safety incidents are not hypothetical: in September 2012, the ferry KMP Bahuga Jaya, carrying over 200 people, collided with the tanker Norgas Cathinka in the strait, killing eight.

What followed the 2007 announcement was not construction but a decade of bureaucratic cycling. Provincial governments in Lampung and Banten formed a consortium. A pre-feasibility study was presented in 2009. President Susilo Bambang Yudhoyono signed a presidential regulation in December 2011 establishing the Sunda Strait Infrastructure and Strategic Zone, with groundbreaking targeted for 2014. South Korea's GS Engineering expressed interest, as did China Railway Construction after an agreement signed during a presidential visit to Beijing in 2012. The U.S. Export-Import Bank signaled willingness to provide long-term finance. But the feasibility study itself kept being delayed. The Ministry of Finance clashed with other ministries over tendering arrangements and preferences for the project consortium. A Jakarta consulting firm assessed the project and concluded it was 'neither financially nor economically viable' on its own merits. Each year brought fresh announcements and fresh postponements.

In November 2014, newly elected President Joko Widodo ended the cycle. His government declared the bridge 'not in line with his maritime-based development vision' and shelved the project indefinitely. The planning minister stated bluntly that the bridge was not an option 'at least not in the next 10 or 15 years.' The government would buy new ships and improve port services instead -- cheaper, faster, less geologically terrifying. Yet the pressures that created the dream have not disappeared. Java, the most populous island on Earth, holds roughly 140 million people. Sumatra is the world's fifth most populous island, with over 50 million. Some twenty million people crossed the strait in 2006, a figure projected to double. Trucks still line up for kilometers at Merak, drivers still wait days, and ferries still battle rough seas during monsoon season. The bridge may be shelved, but the strait still demands a solution.

From the air, the Sunda Strait looks deceptively narrow -- a blue gap between two vast green landmasses, flecked with the wakes of ferries and cargo ships. The volcanic cone of Anak Krakatau, child of the 1883 eruption, rises from the water roughly midway between the proposed bridge endpoints at Anyer on the Java side and Bakauheni on the Sumatra side. The three small islands that would have served as stepping stones for the bridge -- Prajurit, Sangiang, and Ular -- are visible as dark green spots in the channel. It is a landscape that makes the engineering challenge visceral: this is not a placid river crossing but an active geological seam, a passage where tectonic plates collide and volcanoes are born. Whether Indonesia eventually spans it with steel or continues to cross it by sea, the strait will remain one of the archipelago's defining geographic features.