Japan 1937

China is building an "airstrip capable" island in disputed waters of the South China Sea:

China is building an island at least 3,000 m long on Fiery Cross Reef that could be the site for its first airstrip in the Spratly Islands in the South China Sea.
Satellite imagery of the island taken on 8 August and 14 November shows that in the past three months Chinese dredgers have created a land mass that is almost the entire length of the reef.
Fiery Cross Reef lies to the west of the main Spratly island archipelago and was previously under water; the only habitable area was a concrete platform built and maintained by China's People's Liberation Army Navy (PLAN).
The new island is more than 3,000 m long and between 200 and 300 m wide: large enough to construct a runway and apron. The dredgers are also creating a harbour to the east of the reef that would appear to be large enough to receive tankers and major surface combatants.
The existing structure on the reef's southwestern edge was home to a PLAN garrison and had a pier, air-defence guns, anti-frogmen defences, communications equipment, and a greenhouse. The concrete structure is currently not attached to the new island, but if previous Chinese land reclamation projects in the Spratlys are any guide, it is only a matter of time before it is joined up.
The Spratly Islands are claimed by Brunei, China, Malaysia, the Philippines, Taiwan, and Vietnam. All but Brunei occupy islands or have built structures on reefs and shoals to assert their claims.
The land reclamation at Fiery Cross is the fourth such project undertaken by China in the Spratly Islands in the last 12-18 months and by far the largest in scope. China has built new islands at Johnson South Reef, Cuateron Reef, and Gaven Reefs, but none are large enough to house an airstrip in their current form.

Here is the satellite image of the island from Jane's:

Why would China do this?

China has been at a distinct disadvantage compared with other claimants in the Spratly Islands as it is the only claimant not to occupy an island with an airfield. Taiwan has Itu Aba (Taiping) island, the Philippines has Pagasa island, Malaysia has Swallow Reef (a reef on which it reclaimed land and built an airstrip), and Vietnam has Southwest Cay.
The work at Fiery Cross thus brings parity but is likely to cause alarm among the other claimants. China has previously shown it is willing to spend blood and treasure to assert its territorial claims in this region. Given its massive military advantage over the other claimants in terms of quantity and quality of materiel, this facility appears purpose-built to coerce other claimants into relinquishing their claims and possessions, or at least provide China with a much stronger negotiating position if talks over the dispute were ever held.

It seems that China is also taking advantage of the weakness of the US, in the form of the Obama administration's stupidity:

This development comes just days after American officials crowed over the inking of a deal between Beijing and Washington that would decrease the likelihood of military confrontation between the two Pacific naval powers. This despite the fact that the PLA has developed and deployed two brigades of “carrier killer” missiles, a system that the United States reportedly does not have the means to counter. Adding to the apprehension surrounding China’s regional ambitions, the White House has omitted in its annual reports to Congress developments relating to the PLA’s augmentation of its nuclear arsenal since 2010.
“The complete absence of these reports, combined with the administration’s patterns of conciliatory outreach towards Beijing, make it seem like the Obama administration doesn’t want to put public pressure on the Chinese government for its aggressive military developments designed to threaten the U.S.,” The Hill’s Rebeccah Heinrichs reported earlier this month.
America’s aborted pivot to Asia should redouble in the coming months, but it will be doomed to failure if it does not center on a military component. The only way to deter the aggression of revanchist forces in Moscow and Beijing is to confront them with a set of credible military disincentives which might dissuade them from engaging in bellicosity. In the absence of that policy or something similar, Russia has invaded a European state, and China is laying the groundwork for the acquisition of sovereign territory in the Pacific.
Sound familiar?

Yup. Japan 1937.

We are not so much avoiding war as we are delaying it until the cost will be catastrophic.