Complex sentence: Construction was halted the next year, due to lack of funds, and not restarted until after Otto's overthrow in 1863; the plans were then modified by the Greek architect Panagiotis Kalkos, and construction was complete in 1871.
Split into simpler sentences: Construction was halted the next year, due to lack of funds, and not restarted until after Otto's overthrow in 1863. The plans were then modified by the Greek architect Panagiotis Kalkos, and construction finished in 1871.