The main river coursing through Thailand's capital swelled to record highs today amid fears that flood defences could break and swamp the heart of the city.
Ankle-high water from the Chao Phraya river spilled through one sandbagged entranceway of Bangkok's treasured Grand Palace, which once housed the kingdom's monarchy.
The army was pumping out the water, and tourists were still entering the white-walled compound.
The river has filled roads outside the palace gates for days, but the water has receded with the tides, leaving streets dry again.
But the higher than normal tides in the Gulf of Thailand, expected to peak tomorrow, are obstructing the flood runoff from the north, and there are fears that the overflows could swamp parts of the city centre.
The government also is worried major barriers could break.
This morning's high tide passed without a major breach, but the waters briefly touched riverside areas closer to the city's central businesses districts of Silom and Sathorn.
"It is clear that although the high tides haven't reached 2.5 meters, it was high enough to prolong the suffering of those living outside of the flood walls and to threaten those living behind deteriorating walls," Bangkok governor Sukhumbhand Paribatra said.
The flood walls protecting much of the inner city are 2.5 meters (8.2ft), and tomorrow's high tide is expected to reach 2.6 meters (8.5ft).
Seven of Bangkok's 50 districts - all in the northern outskirts - are heavily flooded, and residents have fled aboard bamboo rafts and army trucks and by wading in waist-deep water. Another eight districts have seen less serious flooding.
Fresh flooding was reported today in the city's south-east when a canal overflowed in a neighbourhood on the outer parts of Sukhumvit Road.
The floods, the heaviest in Thailand in more than half a century, have drenched a third of the country's provinces, killed close to 400 people and displaced more than 110,000 others. The water has crept from the central plains south toward the Gulf of Thailand, but Bangkok is in the way. It is literally surrounded by behemoth pools of water flowing around and through the city via a complex network of canals and rivers.
Economic analysts say the floods have cut Thailand's 2011 GDP projections by as much as two percentage points. Damage estimates of 6 billion dollars (£3.7 billion) could double if floods swamp Bangkok.
Most of Bangkok, however, has remained dry and most of its more than nine million residents were staying put to protect their homes. Still, fears the inner city could flood has fuelled an exodus, as Thais and expatriates alike sought refuge outside Bangkok and foreign governments urged their citizens to avoid unessential travel to the threatened city.