It is very difficult to make them out clearly but they appear to be the letters CE, or it could be the letter b.

要将它们清晰的辨认出来并不容易，但是它们貌似是字母ce，或许是字母b。

youdao

According to Vinceti, they appear to be the letters ce or simply the letter B. Other symbols would be hidden in the landscape, more precisely in the arch of the bridge.

据Vinceti称，它们似乎是字母ce或者单个字母b。在背景中，准确地讲是在桥拱中，也可能隐藏着其他的符号。

youdao

According to Vinceti, they appear to be the letters ce or simply the letter B. Other symbols would be hidden in the landscape, more precisely in the arch of the bridge.

据Vinceti称，它们似乎是字母ce或者单个字母b。在背景中，准确地讲是在桥拱中，也可能隐藏着其他的符号。

youdao